This work was supported by IHV clinical division internal funds to JCZ.

In this work, all animal care and procedures were performed according to protocols reviewed and approved by the Institutional Animal Care and Use Committee (IACUC) at the University of Maryland School of Medicine (protocol numbers 1018017, 1018018, and 0318009).
1. Human CD34+ HSC engraftment of newborn mice
<ol>
	<li>Always use disposable personal protection equipment (PPE), including sterile scrubs, gloves, dedicated shoes, shoe covers, mask, goggles, hair/beard bonnet, and sterile lab coats.</li>
	<li>Re-suspend 1 x 106 of frozen CD34+ HSCs (see Table of Materials) in 10 mL of RPMI 1640 media 10% FBS under a certified biosafety cabinet and maintain sterile conditions.</li>
	<li>Use 10 &#181;L of the suspension to count (to assure the presence of the expected number of cells) and check cell viability by trypan blue exclusion staining in a hemocytometer.</li>
	<li>Centrifuge at 400 x g for 15 min at room temperature (RT). Discard the supernatant and resuspend in cold 1x PBS to the required concentration (1.4 x 105 of CD34+ HSCs in 50 &#181;L). Keep the cells on ice until injection.</li>
	<li>Place pups (NS &#947;-chainnull pups of both genders from 1&#8211;4 days old) into a sterile 100 mm2 Petri dish along with a small amount of bedding material from the breeder cage. Additionally, rub clean bedding between hands to further mask any foreign odors on the recipient pups. 
	NOTE: This minimizes foreign odors being impregnated onto the pups, thereby improving the chances of mothers accepting their pups back into cages after the procedure.</li>
	<li>Put the Petri dish into a clean transport cage and place the cage in a clean mouse microisolator cage to protect pups from the environment. Cover the transport cage with a cover pad to avoid exposure of animals to external light while in transit to the irradiation room.</li>
	<li>Irradiate pups with 100 cGy whole body irradiation (WBI) by exposure to a 137 Cs source. Clean the interior of the irradiator with disinfectant solution, place mice in the irradiator, and turn on the turntable so that all pups are irradiated homogeneously. Close the irradiator and press the power switch to initiate the irradiation process. Wait until the irradiation time is completed and immediately remove the mice. 
	NOTE: Since irradiation does not generate stress in the mice, previous anesthesia is not required.</li>
	<li>2&#8211;4 h after the irradiation procedure, place pups in a biosafety cabinet inside a chilled sterile Petri dish covered with sterile gauze on ice, until anesthetized (~5&#8211;10 min). Sufficient anesthesia is achieved when gross movements cease.</li>
	<li>Load the syringe with an attached needle (29 G, 0.5&#34;) with 50 &#181;L of the cell suspension and 1.4 x 105 of CD34+ HSCs under the certified biosafety cabinet.</li>
	<li>For the engraftment via hepatic injection, restrain pups with the thumb and index fingers. To minimize the mouse restraint (~30&#8211;45 s), let one investigator hold the pup and administer the injection, and have the second investigator load the syringe with the HSC suspension. Clean the injection site with 70% alcohol and deliver 50 &#181;L of cells directly into the liver. Use a shallow needle angle when injecting to avoid completely piercing the liver. As a control, inject mice with 50 &#181;L of 1x PBS into the liver.</li>
	<li>Place the pups on a pre-warmed sterile Petri dish covered with sterile gauze for 1&#8211;5 min to allow recovery. Pre-warm the dish using an infrared warming pad for rodents at 20 &#176;C to ensure that pups will not be over-warmed.</li>
	<li>Immediately before returning the pups to their parents, apply a small amount of menthol- and eucalyptus-based ointment, using the thumb and index fingers, to the snout of both parents to avoid cannibalism or rejection of the pups.</li>
	<li>Check cages every day, looking for any signs of graft-versus-host disease (GVHD) in the pups such as dry skin, no feeding, rash, and alopecia. Euthanize the animals if any of these signs are observed.</li>
	<li>Wean mice at 3 weeks of age, grouping them by gender. Do not put more than 5 animals per cage. Verify engraftment in the peripheral blood by flow cytometry at 14 weeks of age. 
	NOTE: The success rate of engraftment is between 80%&#8211;100%.</li>
</ol>
2. Human PBMC engraftment of juvenile mice
<ol>
	<li>For the acute and reactivation models, inject 6&#8211;8 week-old NS &#947;-chainnull mice intraperitoneally with human PBMCs derived from a healthy donor or HIV-infected patient who was under ART, respectively. In both models, include mice injected with PBMCs from a healthy donor without HIV infection (sham) as controls.</li>
	<li>Layer 15 mL of whole blood in 5 mL of sterile density gradient medium into a 50 mL conical tube.</li>
	<li>Centrifuge at 400 x g for 30 min at RT, without brakes, to avoid the buffy coat from becoming mixed with the density gradient medium.</li>
	<li>Carefully collect the fraction of mononuclear cells (between the density gradient medium and supernatant) and transfer the buffy coat to a 15 mL centrifuge tube containing 10 mL of 1x PBS. Centrifuge at 300 x g for 10 min at RT.</li>
	<li>Discard the supernatant and remove the remaining red blood cells by lysing with 5 mL of ACK buffer added to the pelleted cells. Incubate for 4 min at RT.</li>
	<li>Centrifuge at 300 x g for 10 min at RT. Discard the supernatant and resuspend in 10 mL of 1x PBS or RPMI 1640 medium.</li>
	<li>Use 10 &#181;L of the cell suspension to count the cells and check viability by trypan blue exclusion staining in a hemocytometer. Typically, 1&#8211;2 x 106 cells are obtained for each 1 mL of blood, with more than 95% viability.</li>
	<li>Centrifuge at 300 x g for 10 min at RT. Discard the supernatant and adjust the cell number to the required concentration (in this case, 3.5 x 106 cells in 200 &#181;L of 1x PBS).</li>
	<li>Load the syringe with an attached needle (28 G, 0.5&#34;) with 3.5 x 106 of PBMCs in 200 &#181;L of 1x PBS under a certified biosafety cabinet.</li>
	<li>Remove the mouse from the cage and hold it by the tail so that it can grip the mesh, applying gentle traction backward. Then, place the index and thumb fingers on the shoulders of the animal, grabbing the loose skin of the neck and using the middle finger to stabilize its back.</li>
	<li>Slide the mouse head back so that its back is above the head. This allows the viscera in the abdominal cavity to be displaced backward and reduces the risk of puncturing the internal organs during the injection.</li>
	<li>Clean the injection site with 70% alcohol.</li>
	<li>Penetrate the syringe used in step 2.9 through the abdominal wall and aspirate before injecting the cells, if any material is aspirated, remove the syringe and discard it. Otherwise, inject the cells slowly in the intraperitoneal cavity, remove the syringe and discard it. Inject 1x PBS to control mice.</li>
	<li>Return the animal to its cage.</li>
	<li>Verify engraftment in peripheral blood by flow cytometry at 3 weeks post-injection.</li>
</ol>
3. Post-engraftment care
<ol>
	<li>Identify mice by ear tagging.</li>
	<li>Observe the mice used in these experiments closely 2x per day after each procedure for clinical signs of distress.</li>
	<li>After human cells transplantation, monitor mice for GVHD. For monitoring GVHD symptoms in newborn, juvenile, and adult mice, evaluate animals for the appearance of skin disease (i.e., color, dryness, rash, alopecia), in addition to body weight measure. Evaluate animals that show these signs by a veterinarian to consider early euthanasia.</li>
</ol>
4. HIV infection procedure and sham infection procedure
NOTE: For the chronic and acute models, mice are infected with the HIV BaL reference strain at week 14 and week 3 post-engraftment, respectively. Injections with HIV is administered intraperitoneally into the lower abdominal quadrants.
<ol>
	<li>Perform the loading process of the virus/PBS into syringes, using a 28 G 0.5&#34; needle, in BSL2 cabinets following ABSL2 procedures. The total amount of virus injected is 15,000 median tissue culture infectious dose (TCID50) in 200 &#181;L of sterile RPMI 1640.</li>
	<li>Remove the mouse from the cage and hold it by its tail so that it can grip the mesh, applying gentle traction backward. Then, place the index finger and thumb on the shoulders of the animal, grabbing the loose skin of the neck and using the middle finger to stabilize the back.</li>
	<li>Slide the mouse head back so that its back is above its head. This allows the viscera in the abdominal cavity to be displaced backward and reduces the risk of puncturing internal organs during injection.</li>
	<li>Clean the mice with a pre-wetted alcohol pad in the lower left/right quadrant of the abdomen. Inject 15,000 TCID50 of the HIV BaL virus contained in 200 &#181;L of sterile RPMI 1640.</li>
	<li>After injection, return the mouse to its home cage.</li>
</ol>
5. Blood collection by retroorbital puncture
NOTE: Retroorbital bleeding allows for the fast collection of blood, thereby reducing the overall collection time and increasing the stability of human lymphocyte markers. Use EDTA tubes to collect mice blood.
<ol>
	<li>In the chronic model, at 14 weeks post-HSC injection, collect the blood via retroorbital vein. In the acute and reactivation models, perform this procedure at 3 weeks post-PBMC injection.</li>
	<li>Anesthetize the animals using 250 &#181;L of isoflurane inhalation prior to blood collection in a biosafety hood class B2 that is ducted externally.</li>
	<li>Dispense the Isoflurane into cotton pads under a wire mesh in a clear 1 L jar in a biosafety cabinet vented outside of the building. The use of the mesh ensures that the animals do not contact the isoflurane-soaked pad, which can cause skin irritation and potential overdosing since isoflurane is also absorbed through the skin. Also, put a soft paper towel between the mesh and animal to avoid limbs injuries.</li>
	<li>Once the jar is saturated with isoflurane (approximately 1 min after adding it), introduce the animal and observe the respiratory rate, which will increase then decrease. Check for the clinical indication of a deep plane of anesthesia, which includes the lack of a righting reflex (upon tipping jar gently) and lack of gross movements. Start the bleeding procedure as soon as the animal is completely relaxed and lacking the toe pinch reflex. 
	NOTE: Since Isoflurane evaporates, dispense more drug if no signs of anesthesia are observed.</li>
	<li>For the retroorbital bleeding, press the mouse external jugular vein caudal to the mandible with the thumb, and with the same hand, gently elevate the upper eyelid with the index finger.</li>
	<li>Insert a hematocrit tube into the medial canthus of the eye and direct it in a ventrolateral direction until the blood starts fluxing.</li>
	<li>Collect at least 100 &#181;L of blood. Once the desired volume of blood is obtained (a volume no more than the 1% of the body weight of the animal), discontinue the external jugular pressure and remove the hematocrit tube.</li>
	<li>Assure that the hemostasis is complete by applying the direct pressure on the eye using a sterile gauze for a minimum of 30 s.</li>
	<li>Apply tetracaine drops in the eye. Monitor the animal until it has completely recovered from anesthesia and place it back in the cage. 
	NOTE: The 100 &#181;L of collected blood is used for the evaluation of the level of engraftment of human CD45+ and other blood cell populations, as well as for the evaluation of plasma viral load.</li>
</ol>
6. Screening of engraftment level and flow cytometry analysis
<ol>
	<li>Follow a conventional flow cytometry staining protocol for whole blood, which includes the incubation of fluorochrome-labeled anti-human antibodies (for suggested flow panel, see Table of Materials), followed by the lysis of red blood cells and washing steps13,15. 
	NOTE: For the screening of the level of engraftment, include an anti-human CD45 antibody. For the comparison, an anti-mouse CD45 antibody may also be used. Include compensation controls as well as a human blood sample stained with the same antibody mix, unstained mouse and human blood samples, and non-humanized control to test cross-reactivity of the reagents. After staining, there is always some background signal; however, all positive signals are clearly distinguished from negative and cross-reactive controls.</li>
	<li>In an appropriate flow cytometer, acquire at least 10,000 events on the lymphocyte gate (FSC-A vs. SSC-A). For flow cytometry analysis, after duplicate exclusion, determine the percentage of human CD45+ cells as well as other cell populations of interest.</li>
</ol>
7. Evaluation of plasma viral load
<ol>
	<li>Evaluate the viral load in HIV infected animals 1x per week after infection.</li>
	<li>After the retroorbital bleeding (approximately 100 &#181;L), obtain plasma by collecting the supernatant after centrifugation of the anticoagulated blood at 3,500 x g for 3 min in a microcentrifuge. The pellet is used for blood cell phenotyping.</li>
	<li>Use a commercial viral RNA extraction kit (see Table of Materials) to obtain RNA from 40 &#181;L of plasma.</li>
	<li>Convert RNA into cDNA using the first strain synthesis mix (see Table of Materials) and HIV gag primer SK431.</li>
	<li>Perform quantitative real-time PCR using HIV Gag primers SK38/SK39 and fluorescent green dyes (e.g., SYBR green) as described in previous studies13,25.</li>
</ol>
8. Administration of antiretroviral therapy
<ol>
	<li>Administer oral ART at least 3 weeks after infection, when high viral load is observed, in the chronic, acute, and reactivation models.</li>
	<li>Calculate the doses of tenofovir disoproxil fumarate (TDF), emtricitabine (FTC), and raltegravir (RAL), according to Km values of 37 and 3 for humans and mice, respectively26. Typically, the human-equivalent doses of TDF, FTC, and RAL are 61.7 mg/kg/day, 40.7 mg/kg/day, and 164 mg/kg/day, respectively.</li>
	<li>For administration in drinking water, crush drug tablets and add the respective amount in the water bottle, ensuring that each mouse in the cage acquires its daily dose. Since the drug powder may form sediment in the bottle, periodically shake the water bottle to achieve homogeneous suspension.</li>
	<li>Change the water bottle every week with freshly dissolved drugs.</li>
	<li>Collect the blood via retroorbital vein every week or every 2 weeks after ART initiation to evaluate the changes in viral load and CD4:CD8 ratio.</li>
</ol>
9. Mouse euthanasia, collection of secondary lymphoid organs, and isolation of mononuclear cells
<ol>
	<li>Euthanasia is performed in the three humanized mouse models, periodically along infection time, or at the end of the experiment.</li>
	<li>Perform the euthanasia of adult mice by CO2 asphyxiation, followed by the cervical dislocation. For asphyxiation, use a non-precharged chamber, dispense CO2 from a commercial cylinder with fixed pressure regulator and in line restrictor controlling the gas flow within 20%-30% of the chamber volume/minute to comply with 2013 AVMA guidelines.</li>
	<li>Maintain the CO2 flow for &#62;60 s monitoring respiratory arrest (which may take up to 5 min), followed by the cervical dislocation to assure euthanasia.</li>
	<li>Euthanize neonates &#60;7 days old by a physical method (i.e., using sharp scissors).</li>
	<li>Visualize axillary, mediastinal, and mesenteric lymph nodes (which are typically observed) and extract them with tweezers and sharp scissors. Also extract the spleen, located in the upper left side of the peritoneal cavity.</li>
	<li>Deposit the lymphoid tissues in 1.5 mL centrifuge tubes containing sterile RPMI 1640 medium.</li>
	<li>Immediately process the lymphoid tissues in a 70 &#956;m pore-size nylon cell strainer, collecting the cells in a 50 mL tube. Do not aspirate the tissues.</li>
	<li>Wash the cells with 5 mL of RPMI 1640 medium supplemented with 1% FBS to facilitate cells filtering.</li>
	<li>After the tissue disaggregation, centrifuge the cells suspension at 3,500 x g for 10 min in a microcentrifuge.</li>
	<li>Discard the supernatant and resuspend the cells with 500 &#181;L of 1x PBS.</li>
	<li>Transfer the cells suspension into a 1.5 mL centrifuge tube containing 500 &#181;L of sterile density gradient medium.</li>
	<li>Centrifuge at 3,500 x g for 3 min in a microcentrifuge, without brake, to prevent the buffy coat from mixing with the density gradient medium</li>
	<li>Carefully collect the fraction of mononuclear cells (between the density gradient medium and supernatant) and transfer the buffy coat to a 1.5 mL centrifuge tube containing 500 &#181;L of 1x PBS. Centrifuge at 3,000 x g for 3 min.</li>
	<li>Remove the remaining red blood cells by lysing with 500 &#181;L of ACK buffer, incubating for 4 min at RT.</li>
	<li>Centrifuge at 3,000 x g for 3 min. Discard the supernatant and resuspend in 1 mL of 1x PBS or medium.</li>
</ol>

<ol>
	<li>Shultz, L. D., Ishikawa, F., Greiner, D. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Humanized+mice+in+translational+biomedical+research.">Humanized mice in translational biomedical research.</a> Nature Reviews Immunology. 7, 118-130 (2007).</li><li>Koboziev, I., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Use+of+humanized+mice+to+study+the+pathogenesis+of+autoimmune+and+inflammatory+diseases.">Use of humanized mice to study the pathogenesis of autoimmune and inflammatory diseases.</a> Inflammatory Bowel Diseases. 21 (7), 1652-1673 (2015).</li><li>Ito, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=NOD/SCID/&#947;cnull+mouse:+An+excellent+recipient+mouse+model+for+engraftment+of+human+cells.">NOD/SCID/&#947;cnull mouse: An excellent recipient mouse model for engraftment of human cells.</a> Blood. 100 (9), 3175-3182 (2002).</li><li>Ishikawa, F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+functional+human+blood+and+immune+systems+in+NOD/SCID/IL2+receptor+{gamma}+chain(null)+mice.">Development of functional human blood and immune systems in NOD/SCID/IL2 receptor {gamma} chain(null) mice.</a> Blood. 106 (5), 1565-1573 (2005).</li><li>Kim, K. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Simple+Mouse+Model+for+the+Study+of+Human+Immunodeficiency+Virus.">A Simple Mouse Model for the Study of Human Immunodeficiency Virus.</a> AIDS research and human retroviruses. 32 (2), 194-202 (2016).</li><li>Wunderlich, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=AML+xenograft+efficiency+is+significantly+improved+in+NOD/SCID-IL2RG+mice+constitutively+expressing+human+SCF,+GM-CSF+and+IL-3.">AML xenograft efficiency is significantly improved in NOD/SCID-IL2RG mice constitutively expressing human SCF, GM-CSF and IL-3.</a> Leukemia. 24 (10), 1785-1788 (2010).</li><li>Billerbeck, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+human+CD4+FoxP3++regulatory+T+cells+in+human+stem+cell+factor-,+granulocyte-macrophage+colony-stimulating+factor-,+and+interleukin-3-expressing+NOD-SCID+IL2R&#947;null+humanized+mice.">Development of human CD4+FoxP3+ regulatory T cells in human stem cell factor-, granulocyte-macrophage colony-stimulating factor-, and interleukin-3-expressing NOD-SCID IL2R&#947;null humanized mice.</a> Blood. 117 (11), 3076-3086 (2011).</li><li>Coughlan, A. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Myeloid+Engraftment+in+Humanized+Mice:+Impact+of+Granulocyte-Colony+Stimulating+Factor+Treatment+and+Transgenic+Mouse+Strain.">Myeloid Engraftment in Humanized Mice: Impact of Granulocyte-Colony Stimulating Factor Treatment and Transgenic Mouse Strain.</a> Stem cells and development. 25 (7), 530-541 (2016).</li><li>Kumar, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=T+Cell-Specific+siRNA+Delivery+Suppresses+HIV-1+Infection+in+Humanized+Mice.">T Cell-Specific siRNA Delivery Suppresses HIV-1 Infection in Humanized Mice.</a> Cell. 134 (4), 577-586 (2008).</li><li>Victor Garcia, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Humanized+mice+for+HIV+and+AIDS+research.">Humanized mice for HIV and AIDS research.</a> Current Opinion in Virology. 19, 56-64 (2016).</li><li>Ara&#237;nga, M., Su, H., Poluektova, L. Y., Gorantla, S., Gendelman, H. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=HIV-1+cellular+and+tissue+replication+patterns+in+infected+humanized+mice.">HIV-1 cellular and tissue replication patterns in infected humanized mice.</a> Scientific Reports. 6, 1-12 (2016).</li><li>Satheesan, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=HIV+replication+and+latency+in+a+humanized+NSG+mouse+model+during+suppressive+oral+combinational+ART.">HIV replication and latency in a humanized NSG mouse model during suppressive oral combinational ART.</a> Journal of Virology. 92 (7), 2118 (2018).</li><li>Medina-Moreno, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Targeting+of+CDK9+with+indirubin+3&#8217;-monoxime+safely+and+durably+reduces+HIV+viremia+in+chronically+infected+humanized+mice.">Targeting of CDK9 with indirubin 3&#8217;-monoxime safely and durably reduces HIV viremia in chronically infected humanized mice.</a> PLoS ONE. 12 (8), 1-13 (2017).</li><li>Honeycutt, J. B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Macrophages+sustain+HIV+replication+in+vivo+independently+of+T+cells.">Macrophages sustain HIV replication in vivo independently of T cells.</a> The Journal of Clinical Investigation. 126 (4), 1353-1366 (2016).</li><li>Perdomo-Celis, F., Medina-Moreno, S., Davis, H., Bryant, J., Zapata, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=HIV+Replication+in+Humanized+IL-3/GM-CSF-Transgenic+NOG+Mice.">HIV Replication in Humanized IL-3/GM-CSF-Transgenic NOG Mice.</a> Pathogens. 8 (33), 1-16 (2019).</li><li>Akkina, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improvements+and+Limitations+of+Humanized+Mouse+Models+for+HIV+Research:+NIH/NIAID+"Meet+the+Experts"+2015+Workshop+Summary.">Improvements and Limitations of Humanized Mouse Models for HIV Research: NIH/NIAID "Meet the Experts" 2015 Workshop Summary.</a> AIDS Research and Human Retroviruses. 32 (2), 109-119 (2015).</li><li>Dudek, T. E., Allen, T. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=HIV-Specific+CD8++T-Cell+Immunity+in+Humanized+Bone+Marrow-Liver-Thymus+Mice.">HIV-Specific CD8+ T-Cell Immunity in Humanized Bone Marrow-Liver-Thymus Mice.</a> The Journal of Infectious Diseases. 208, 150-154 (2013).</li><li>Skelton, J. K., Ortega-Prieto, A. M., Dorner, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Hitchhiker's+guide+to+humanized+mice:+new+pathways+to+studying+viral+infections.">A Hitchhiker's guide to humanized mice: new pathways to studying viral infections.</a> Immunology. 154, 50-61 (2018).</li><li>Pearson, T., Greiner, D. L., Shultz, L. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Creation+of+"humanized"+mice+to+study+human+immunity.">Creation of "humanized" mice to study human immunity.</a> Current Protocols in Immunology. , (2008).</li><li>Hasgur, S., Aryee, K. E., Shultz, L. D., Greiner, D. L., Brehm, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Generation+of+Immunodeficient+Mice+Bearing+Human+Immune+Systems+by+the+Engraftment+of+Hematopoietic+Stem+Cells.">Generation of Immunodeficient Mice Bearing Human Immune Systems by the Engraftment of Hematopoietic Stem Cells.</a> Methods in molecular biology. 1438, 67-78 (2016).</li><li>Shultz, L. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Human+lymphoid+and+myeloid+cell+development+in+NOD/LtSz-scid+IL2R+gamma+null+mice+engrafted+with+mobilized+human+hemopoietic+stem+cells.">Human lymphoid and myeloid cell development in NOD/LtSz-scid IL2R gamma null mice engrafted with mobilized human hemopoietic stem cells.</a> Journal of Immunology. 174 (10), 6477-6489 (2005).</li><li>King, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+new+Hu-PBL+model+for+the+study+of+human+islet+alloreactivity+based+on+NOD-scid+mice+bearing+a+targeted+mutation+in+the+IL-2+receptor+gamma+chain+gene.">A new Hu-PBL model for the study of human islet alloreactivity based on NOD-scid mice bearing a targeted mutation in the IL-2 receptor gamma chain gene.</a> Clinical Immunology. 126 (3), 303-314 (2008).</li><li>King, M. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Human+peripheral+blood+leucocyte+non-obese+diabetic-severe+combined+immunodeficiency+interleukin-2+receptor+gamma+chain+gene+mouse+model+of+xenogeneic+graft-versus-host-like+disease+and+the+role+of+host+major+histocompatibility+complex.">Human peripheral blood leucocyte non-obese diabetic-severe combined immunodeficiency interleukin-2 receptor gamma chain gene mouse model of xenogeneic graft-versus-host-like disease and the role of host major histocompatibility complex.</a> Clinical and Experimental Immunology. 157 (1), 104-118 (2009).</li><li>Covassin, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Human+peripheral+blood+CD4+T+cell-engrafted+non-obese+diabetic-scid+IL2rgamma(null)+H2-Ab1+(tm1Gru)+Tg+(human+leucocyte+antigen+D-related+4)+mice:+a+mouse+model+of+human+allogeneic+graft-versus-host+disease.">Human peripheral blood CD4 T cell-engrafted non-obese diabetic-scid IL2rgamma(null) H2-Ab1 (tm1Gru) Tg (human leucocyte antigen D-related 4) mice: a mouse model of human allogeneic graft-versus-host disease.</a> Clinical and experimental immunology. 166 (2), 269-280 (2011).</li><li>Heredia, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Targeting+of+mTOR+catalytic+site+inhibits+multiple+steps+of+the+HIV-1+lifecycle+and+suppresses+HIV-1+viremia+in+humanized+mice.">Targeting of mTOR catalytic site inhibits multiple steps of the HIV-1 lifecycle and suppresses HIV-1 viremia in humanized mice.</a> Proceedings of the National Academy of Sciences of the United States of America. 112 (30), 9412-9417 (2015).</li><li>Nair, A., Jacob, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+simple+practice+guide+for+dose+conversion+between+animals+and+human.">A simple practice guide for dose conversion between animals and human.</a> Journal of Basic and Clinical Pharmacy. 7 (2), 27-31 (2016).</li><li>Miller, P. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analysis+of+parameters+that+affect+human+hematopoietic+cell+outputs+in+mutant+c-kit-immunodeficient+mice.">Analysis of parameters that affect human hematopoietic cell outputs in mutant c-kit-immunodeficient mice.</a> Experimental Hematology. 48, 41-49 (2017).</li><li>Murphy, W. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Induction+of+T+cell+differentiation+and+lymphomagenesis+in+the+thymus+of+mice+with+severe+combined+immune+deficiency+(SCID).">Induction of T cell differentiation and lymphomagenesis in the thymus of mice with severe combined immune deficiency (SCID).</a> Journal of Immunology. 153 (3), 1004-1014 (1994).</li><li>Poluektova, L. Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Humanized+Mice+as+Models+for+Human+Disease.">Humanized Mice as Models for Human Disease.</a> Humanized Mice for HIV Research. , 15-24 (2015).</li><li>Nakata, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Potent+anti-R5+human+immunodeficiency+virus+type+1+effects+of+a+CCR5+antagonist,+AK602/ONO4128/GW873140,+in+a+novel+human+peripheral+blood+mononuclear+cell+nonobese+diabetic-SCID,+interleukin-2+receptor+gamma-chain-knocked-out+AIDS+mouse+model.">Potent anti-R5 human immunodeficiency virus type 1 effects of a CCR5 antagonist, AK602/ONO4128/GW873140, in a novel human peripheral blood mononuclear cell nonobese diabetic-SCID, interleukin-2 receptor gamma-chain-knocked-out AIDS mouse model.</a> Journal of Virology. 79 (4), 2087-2096 (2005).</li><li>Terahara, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fluorescent+Reporter+Signals,+EGFP,+and+DsRed,+Encoded+in+HIV-1+Facilitate+the+Detection+of+Productively+Infected+Cells+and+Cell-Associated+Viral+Replication+Levels.">Fluorescent Reporter Signals, EGFP, and DsRed, Encoded in HIV-1 Facilitate the Detection of Productively Infected Cells and Cell-Associated Viral Replication Levels.</a> Frontiers in Microbiology. 2, 280 (2012).</li><li>Nicolini, F. E., Cashman, J. D., Hogge, D. E., Humphries, R. K., Eaves, C. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=NOD/SCID+mice+engineered+to+express+human+IL-3,+GM-CSF+and+Steel+factor+constitutively+mobilize+engrafted+human+progenitors+and+compromise+human+stem+cell+regeneration.">NOD/SCID mice engineered to express human IL-3, GM-CSF and Steel factor constitutively mobilize engrafted human progenitors and compromise human stem cell regeneration.</a> Leukemia. 18 (2), 341-347 (2004).</li><li>Cyster, J. G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Follicular+stromal+cells+and+lymphocyte+homing+to+follicles.">Follicular stromal cells and lymphocyte homing to follicles.</a> Immunological Reviews. 176, 181-193 (2000).</li><li>Seung, E., Tager, A. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Humoral+Immunity+in+Humanized+Mice:+A+Work+in+Progress.">Humoral Immunity in Humanized Mice: A Work in Progress.</a> Journal of Infectious Diseases. 208, 155-159 (2013).</li><li>Wahl, A., Victor Garcia, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+use+of+BLT+humanized+mice+to+investigate+the+immune+reconstitution+of+the+gastrointestinal+tract.">The use of BLT humanized mice to investigate the immune reconstitution of the gastrointestinal tract.</a> Journal of Immunological Methods. 410, 28-33 (2014).</li><li>Suzuki, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Induction+of+human+humoral+immune+responses+in+a+novel+HLA-DR-expressing+transgenic+NOD/Shi-scid/&#947;c+null+mouse.">Induction of human humoral immune responses in a novel HLA-DR-expressing transgenic NOD/Shi-scid/&#947;c null mouse.</a> International Immunology. 24 (4), 243-252 (2012).</li><li>Ali, N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Xenogeneic+Graft-versus-Host-Disease+in+NOD-scid+IL-2R&#947;null+Mice+Display+a+T-Effector+Memory+Phenotype.">Xenogeneic Graft-versus-Host-Disease in NOD-scid IL-2R&#947;null Mice Display a T-Effector Memory Phenotype.</a> PLoS ONE. 7 (8), 1-10 (2012).</li><li>Brehm, M. A., Wiles, M. V., Greiner, D. L., Shultz, L. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Generation+of+improved+humanized+mouse+models+for+human+infectious+diseases.">Generation of improved humanized mouse models for human infectious diseases.</a> Journal of Immunological Methods. 410, 3-17 (2014).</li><li>Hakre, S., Chavez, L., Shirakawa, K., Verdin, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=HIV+latency:+experimental+systems+and+molecular+models.">HIV latency: experimental systems and molecular models.</a> FEMS Microbiology Reviews. 36 (3), 706-716 (2012).</li><li>Wu, F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=TRIM5&#945;+Restriction+Affects+Clinical+Outcome+and+Disease+Progression+in+Simian+Immunodeficiency+Virus-Infected+Rhesus+Macaques.">TRIM5&#945; Restriction Affects Clinical Outcome and Disease Progression in Simian Immunodeficiency Virus-Infected Rhesus Macaques.</a> Journal of Virology. 89 (4), 2233 (2015).</li></ol>

The authors have nothing to disclose.

Important advances have been achieved in the development of immunodeficient mouse strains for humanization, with a number of different options that can be used according to the research interest1. Provided here is a general protocol for the humanization of NS &#947;-chainnull mice and genetically similar strains to be employed in three different models for studying HIV infection. In the first experimental approach, irradiated newborn mice are injected with human CD34+ HSCs, w...

The humanized NOD/SCID/interleukin (IL)-2 receptor &#947;-chainnull (hereafter referred to as huNS &#947;-chainnull) mouse model has been widely used for studying the pathogenesis of infections, autoimmunity, and cancer, as well as for pre-clinical studies of drugs and human cell-based therapies1,2. These mice are based on a non-obese diabetic (NOD) background, with the scid mutation and targeted mutation at the IL-2 receptor &#947;-chain locus (common &#947;-chain for IL-2, IL-4, IL-7, IL-9, IL-15, and IL-21), which induce a severe impairment in the development of mouse T-, B-, and natural killer (NK) cells1. Thus, they support the engraftment of human tissue, human CD34+ hematopoietic stem cells (HSCs), and human peripheral blood mononuclear cells (PBMCs)3,4,5. In addition, transgenic expression of human hematopoietic factors, such as stem cell factor (SCF), granulocyte/macrophage colony-stimulating factor (GM-CSF), and IL-3 promotes the engraftment of human myeloid populations6,7,8.
For HIV studies, several huNS &#947;-chainnull mouse models have been described, which differ in the mouse strain, type of human cells used, type of tissues for the engraftment, and origin of cells (i.e., healthy vs. HIV-infected donor)9,10. The original strain, however, is widely used due to the high levels of human cells engraftment and viral replication following infection with a reference HIV strain11,12,13. Similar immunodeficient mouse strains with transgenic expression of human hematopoietic factors (e.g., NOG-EXL or NSG-SGM3) or with implants of human liver and thymus tissues (bone marrow-liver-thymus [BLT] mice) are useful for evaluating the role of myeloid populations in the anti-HIV immune response, effects of HIV on these tissues, and their participation as viral reservoirs14,15. Furthermore, some strains with transgenic expression of human leukocyte antigen (HLA) molecules, as well as BLT mice, can be used for studying the T-cell response to HIV infection16,17.
In general, in these mice, humanization depends on the cellular origin, delivery route (intraperitoneal, intrahepatic, intravenous, intracardiac) and mouse age at the time of engraftment18,19,20. Regarding the cell origin, human CD34+ HSC derived from cord blood, fetal liver, or mobilized peripheral blood can be injected in newborn or young mice3,21. In addition, adult &#947;-chainnull mice can be humanized by the injection of PBMC (here, referred to as hu-PBL-NS &#947;-chainnull mice), allowing the temporal circulation of these cells in the blood, secondary lymphoid organs, and inflamed tissues22,23,24.
Described here is a detailed protocol for the establishment of huNS &#947;-chainnull mouse models for the study of HIV infection. The first is the chronic model, in which human CD34+ HSCs derived from cord blood from a healthy donor are injected in newborn mice, followed by infection with a reference HIV strain after 14 weeks of human immune system reconstitution. This model allows monitoring of mice for up to ~36 weeks after infection. The second model is an acute model, in which PBMCs derived from a healthy donor are injected in adult NS &#947;-chainnull mice, followed by infection with a reference HIV strain after 3 weeks of human T-cell expansion in the mouse. Finally, the third model is the reactivation model, in which PBMCs derived from an HIV-infected donor under suppressive antiretroviral therapy (ART) are injected in adult NS &#947;-chainnull mice. In this case, a drug-free environment allows for viral reactivation and increase in the viral load. The two latter models allow monitoring for up to ~9 weeks after engraftment.
Overall, these three models are useful for virological studies, pre-clinical studies of novel drugs, and evaluation of HIV infection effects on the global immune response. It is also important to consider that use of HIV-infected humanized mice requires review and approval by the Institutional Biosafety Committee (IBC) as well as by the Institutional Animal Care and Use Committee (IACUC) before any experiment. This ensures that the study follows all internal and external institutional regulations for the use of hazardous biological material and humane handling of experimental animals.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>0. 5 ml Microcentrifuge tubes</td>
			<td>Neptune</td>
			<td>3735.S.X</td>
			<td></td>
		</tr>
		<tr>
			<td>1. 5 ml Microcentrifuge tubes</td>
			<td>Neptune</td>
			<td>3745.S.X</td>
			<td></td>
		</tr>
		<tr>
			<td>10 ml Serologial pipetes</td>
			<td>stellar sceintific</td>
			<td>VL-4090-0010</td>
			<td></td>
		</tr>
		<tr>
			<td>15 ml conical tubes</td>
			<td>Stellar scientific</td>
			<td>T15-600</td>
			<td></td>
		</tr>
		<tr>
			<td>25 ml Serologial pipetes</td>
			<td>stellar sceintific</td>
			<td>VL-4090-0025</td>
			<td></td>
		</tr>
		<tr>
			<td>5 ml Serologial pipetes</td>
			<td>stellar sceintific</td>
			<td>VL-4090-0005</td>
			<td></td>
		</tr>
		<tr>
			<td>50 ml conical tubes</td>
			<td>Stellar scientific</td>
			<td>T50-600</td>
			<td></td>
		</tr>
		<tr>
			<td>ACK lysis buffer</td>
			<td>Quality biological</td>
			<td>118-156-101</td>
			<td></td>
		</tr>
		<tr>
			<td>Alcohol prep pads</td>
			<td>Fisher scientific</td>
			<td>06-669-62</td>
			<td>Sterile</td>
		</tr>
		<tr>
			<td>Anti-Human CD3 clone UCHT1</td>
			<td>Biolegend</td>
			<td>300439</td>
			<td>APC conjugated</td>
		</tr>
		<tr>
			<td>Anti-Human CD4 clone OKT4</td>
			<td>Biolegend</td>
			<td>317420</td>
			<td>AF488 conjugated</td>
		</tr>
		<tr>
			<td>Anti-Human CD45 clone 2D1</td>
			<td>Biolegend</td>
			<td>368522</td>
			<td>BV421 conjugated</td>
		</tr>
		<tr>
			<td>Anti-Human CD8 clone SK1</td>
			<td>Biolegend</td>
			<td>344710</td>
			<td>PerCP-Cy5.5 conjugated</td>
		</tr>
		<tr>
			<td>Biosafaty cabinet level 2</td>
			<td></td>
			<td></td>
			<td>If posible connected to an exauste chimeny when handling Isoflurane</td>
		</tr>
		<tr>
			<td>Bonnet</td>
			<td>Fisher scientific</td>
			<td>17-100-900</td>
			<td>Single use cap for basic protection</td>
		</tr>
		<tr>
			<td>Cavicide</td>
			<td>Metrex</td>
			<td>13-1000</td>
			<td>Surface desinfectant</td>
		</tr>
		<tr>
			<td>CD34+ cells</td>
			<td>Lonza</td>
			<td>2C-101</td>
			<td>As many vials available from a single donor</td>
		</tr>
		<tr>
			<td>Centrifuge</td>
			<td>Beckman</td>
			<td>65-6KR</td>
			<td></td>
		</tr>
		<tr>
			<td>Clear jar</td>
			<td>Amazon</td>
			<td>77977</td>
			<td></td>
		</tr>
		<tr>
			<td>Cotton gauze pad</td>
			<td>Fisher scientific</td>
			<td>22-415-468</td>
			<td>Sterile</td>
		</tr>
		<tr>
			<td>Disposable lab coats</td>
			<td>Fisher scientific</td>
			<td>19-472-422</td>
			<td></td>
		</tr>
		<tr>
			<td>EDTA micro tubes</td>
			<td>Greiner bio-one</td>
			<td>450480</td>
			<td></td>
		</tr>
		<tr>
			<td>Face Mask</td>
			<td>Fisher scientific</td>
			<td>17-100-897</td>
			<td></td>
		</tr>
		<tr>
			<td>FACS lysing solution</td>
			<td>BD</td>
			<td>340202</td>
			<td></td>
		</tr>
		<tr>
			<td>FBS premium HI</td>
			<td>Atlanta biologicals</td>
			<td>S1115OH</td>
			<td></td>
		</tr>
		<tr>
			<td>Ficoll</td>
			<td>GE health one</td>
			<td>17-1440-02</td>
			<td></td>
		</tr>
		<tr>
			<td>Flow cytometer</td>
			<td></td>
			<td></td>
			<td>We used FACS Aria II</td>
		</tr>
		<tr>
			<td>Flow cytometry tubes</td>
			<td>Falcon</td>
			<td>352054</td>
			<td>5 ml polystyrene and round bottom</td>
		</tr>
		<tr>
			<td>HIV BaL</td>
			<td></td>
			<td></td>
			<td>Prepared in our uQUANT core facility</td>
		</tr>
		<tr>
			<td>Human PBMCs</td>
			<td></td>
			<td></td>
			<td>HIV positive and negative volunteers</td>
		</tr>
		<tr>
			<td>Infrared warming pad</td>
			<td>Venet scientific</td>
			<td>DCT-25</td>
			<td>Temporary therapeutic warming pad for small animals</td>
		</tr>
		<tr>
			<td>Isentress (Raltegravir)</td>
			<td>Merck</td>
			<td>NSC 0006-0227061</td>
			<td>Antiretroviral medication to treat human immunodeficiency virus (HIV)-Integrase inhibitor</td>
		</tr>
		<tr>
			<td>Isoflurane</td>
			<td>Henry Schein</td>
			<td>NDC 11695-6776-2</td>
			<td></td>
		</tr>
		<tr>
			<td>Mark I irradiator</td>
			<td></td>
			<td></td>
			<td>Equipment belonging to university of Maryland</td>
		</tr>
		<tr>
			<td>Micro pipettes</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Microcentrifuge</td>
			<td>Eppendorf</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Mouse ear tags</td>
			<td>National Band &#38; Tag company</td>
			<td>1005-1L1</td>
			<td></td>
		</tr>
		<tr>
			<td>Natelson blood collection tubes</td>
			<td>Fisher scientific</td>
			<td>02-668-10</td>
			<td></td>
		</tr>
		<tr>
			<td>NOG-EXL</td>
			<td>Taconic</td>
			<td>HSCFTL-13395-F</td>
			<td></td>
		</tr>
		<tr>
			<td>NSG mice</td>
			<td>Jackson</td>
			<td>5557</td>
			<td>Time pregnant females for CD34 engraftment and Juveniles for PBMCs engraftment</td>
		</tr>
		<tr>
			<td>NSG-SGM3</td>
			<td>Jackson</td>
			<td>13062</td>
			<td></td>
		</tr>
		<tr>
			<td>Paraformaldehyde 16%</td>
			<td>Electron microscopy sciences</td>
			<td>15710</td>
			<td></td>
		</tr>
		<tr>
			<td>PBS 1X pH 7.4</td>
			<td>Gibco</td>
			<td>100-10-023</td>
			<td></td>
		</tr>
		<tr>
			<td>Petri dishes</td>
			<td>Fisher scientific</td>
			<td>08-757-28</td>
			<td></td>
		</tr>
		<tr>
			<td>Quantistudio qPCR machine</td>
			<td>Thermo</td>
			<td>QS3</td>
			<td></td>
		</tr>
		<tr>
			<td>Reagent reservoirs</td>
			<td>Costar</td>
			<td>4870</td>
			<td></td>
		</tr>
		<tr>
			<td>RPMI media 1640 1X</td>
			<td>Gibco</td>
			<td>11875-093</td>
			<td></td>
		</tr>
		<tr>
			<td>Shoe covers</td>
			<td>Fisher scientific</td>
			<td>17-100-911</td>
			<td></td>
		</tr>
		<tr>
			<td>Sterile disposable Gloves</td>
			<td>Microflex</td>
			<td>SUF-524</td>
			<td></td>
		</tr>
		<tr>
			<td>SuperScript II First-Strand Synthesis SuperMix</td>
			<td>Invitrogen</td>
			<td>10080-400</td>
			<td>cDNA synthesis</td>
		</tr>
		<tr>
			<td>Syringes 28-G x 1/2</td>
			<td>BD</td>
			<td>329-461</td>
			<td></td>
		</tr>
		<tr>
			<td>Syringes 29-G x 1/2</td>
			<td>BD</td>
			<td>324-702</td>
			<td></td>
		</tr>
		<tr>
			<td>Truvada (Emtricitabine and Tenofovir</td>
			<td>Gilead</td>
			<td>NDC 61958-0701-1</td>
			<td>Antiretroviral medication to treat human immunodeficiency virus (HIV)-Nicleoside analog-transcriptase inhibitor</td>
		</tr>
		<tr>
			<td>Trypan blue</td>
			<td>Sigma</td>
			<td>T8154</td>
			<td>Cell count and viability</td>
		</tr>
		<tr>
			<td>Vick Vaporub</td>
			<td>School health</td>
			<td>43214</td>
			<td>Ointment based on menthol and eucalyptus</td>
		</tr>
		<tr>
			<td>Water molecular biology grade</td>
			<td>Quality biological</td>
			<td>351-029-131</td>
			<td></td>
		</tr>
	</tbody>
</table>

chronic, acute, and reactivated hiv infection in humanized immunodeficient mouse models

Humanized NOD/SCID/IL-2 receptor &#947;-chainnull mice recapitulate some features of human immunity, which can be exploited in basic and pre-clinical research on infectious diseases. Described here are three models of humanized immunodeficient mice for studying the dynamics of HIV infection. The first is based on the intrahepatic injection of CD34+ hematopoietic stem cells in newborn mice, which allows for the reconstitution of several blood and lymphoid tissue-confined cells, followed by infection with a reference HIV strain. This model allows monitoring for up to 36 weeks post-infection and is hence called the chronic model. The second and third models are referred to as the acute and reactivation models, in which peripheral blood mononuclear cells are intraperitoneally injected in adult mice. In the acute model, cells from a healthy donor are engrafted through the intraperitoneal route, followed by infection with a reference HIV strain. Finally, in the reactivation model, cells from an HIV-infected donor under antiretroviral therapy are engrafted via the intraperitoneal route. In this case, a drug-free environment in the mouse allows for virus reactivation and an increase in viral load. The protocols provided here describe the conventional experimental approach for humanized, immunodeficient mouse models of HIV infection.

As described above, at 14 weeks post-HSC injection (chronic model) or at 3 weeks post-PBMC injection (acute and reactivation models), the mice are bled for screening the level of human cells engraftment by flow cytometry. A representative gating strategy for the evaluation of 1) human CD45+ cells reconstitution and 2) percentage of CD4+ and CD8+ T-cells is shown in Figure 1A. Typically, the level of engraftment (percentage of human CD45+...

Watch this Scientific Journal Video about Chronic, Acute, and Reactivated HIV Infection in Humanized Immunodeficient Mouse Models at JoVE.com

Chronic, Acute, and Reactivated HIV Infection in Humanized Immunodeficient Mouse Models

Described here are three experimental approaches for studying the dynamics of HIV infection in humanized mice. The first permits the study of chronic infection events, whereas the two latter allows for the study of acute events after primary infection or viral reactivation.

Humanized NOD/SCID/IL-2 receptor &#947;-chainnull mice recapitulate some features of human immunity, which can be exploited in basic and pre-clinical ...

chronic-acute-reactivated-hiv-infection-humanized-immunodeficient

Research

JoVE Journal

Immunology and Infection

8.3K Views.  University of Maryland. Described here are three experimental approaches for studying the dynamics of HIV infection in humanized mice. The first permits the study of chronic infection events, whereas the two latter allows for the study of acute events after primary infection or viral reactivation.

Video: Chronic, Acute, and Reactivated HIV Infection in Humanized Immunodeficient Mouse Models

Genotypic Inference of HIV-1 Tropism Using Population-based Sequencing of V3

Background: Prior to receiving a drug from CCR5-antagonist class in HIV therapy, a patient must undergo an HIV tropism test to confirm that his or her viral population uses the CCR5 coreceptor for cellular entry, and not an alternative coreceptor. One approach to tropism testing is to examine the sequence of the V3 region of the HIV envelope, which interacts with the coreceptor.
Methods: Viral RNA is extracted from blood plasma. The V3 region is amplified in triplicate with nested reverse transcriptase-PCR. The amplifications are then sequenced and analyzed using the software, RE_Call. Sequences are then submitted to a bioinformatic algorithm such as geno2pheno to infer viral tropism from the V3 region. Sequences are inferred to be non-R5 if their geno2pheno false positive rate falls below 5.75%. If any one of the three sequences from a sample is inferred to be non-R5, the patient is unlikely to respond to a CCR5-antagonist.

HIV tropism can be inferred from the V3 region of the viral envelope. V3 is PCR amplified in triplicate using nested RT-PCR, sequenced, and interpreted using bioinformatic software. Samples with with 1 or more sequence(s) with low g2P scores are classified as non-R5 virus.

Background: Prior to receiving a drug from CCR5-antagonist class in HIV therapy, a patient must undergo an HIV tropism test to confirm that his or her ...

In vitro Uncoating of HIV-1 Cores

The genome of the retroviruses is encased in a capsid surrounded by a lipid envelope. For lentiviruses, such as HIV-1, the conical capsid shell is composed of CA protein arranged as a lattice of hexagon. The capsid is closed by 7 pentamers at the broad end and 5 at the narrow end of the cone1, 2. Encased in this capsid shell is the viral ribonucleoprotein complex, and together they comprise the core.
Following fusion of the viral membrane with the target cell membrane, the HIV-1 is released into the cytoplasm. The capsid then disassembles releasing free CA in the soluble form3 in a process referred to as uncoating. The intracellular location and timing of HIV-1 uncoating are poorly understood. Single amino-acid substitutions in CA that alter the stability of the capsid also impair the ability of HIV-1 to infect cells4. This indicates that the stability of the capsid is critical for HIV-1 infection.
HIV-1 uncoating has been difficult to study due to lack of availability of sensitive and reliable assays for this process. Here we describe a quantitative method for studying uncoating in vitro using cores isolated from infectious HIV-1 particles. The approach involves isolation of cores by sedimentation of concentrated virions through a layer of detergent and into a linear sucrose gradient, in the cold. To quantify uncoating, the isolated cores are incubated at 37&deg;C for various timed intervals and subsequently pelleted by ultracentrifugation. The extent of uncoating is analyzed by quantifying the fraction of CA in the supernatant. This approach has been employed to analyze effects of viral mutations on HIV-1 capsid stability4, 5, 6. It should also be useful for studying the role of cellular factors in HIV-1 uncoating.

In vitro Uncoating of HIV-1 Cores

Uncoating is an essential step in the early phase of the HIV-1 life cycle and is defined as the disassembly of the capsid shell and the release of the viral ribonucleoprotein complex (vRNP). Here, we demonstrate techniques for isolating intact cores from HIV-1 virions and for quantifying their uncoating in vitro.

The genome of the retroviruses is encased in a capsid surrounded by a lipid envelope. For lentiviruses, such as HIV-1, the conical capsid shell is ...

In vivo Imaging Method to Distinguish Acute and Chronic Inflammation

Inflammation is a fundamental aspect of many human diseases. In this video report, we demonstrate non-invasive bioluminescence imaging techniques that distinguish acute and chronic inflammation in mouse models. With tissue damage or pathogen invasion, neutrophils are the first line of defense, playing a major role in mediating the acute inflammatory response. As the inflammatory reaction progresses, circulating monocytes gradually migrate into the site of injury and differentiate into mature macrophages, which mediate chronic inflammation and promote tissue repair by removing tissue debris and producing anti-inflammatory cytokines. Intraperitoneal injection of luminol (5-amino-2,3-dihydro-1,4-phthalazinedione, sodium salt) enables detection of acute inflammation largely mediated by tissue-infiltrating neutrophils. Luminol specifically reacts with the superoxide generated within the phagosomes of neutrophils since bioluminescence results from a myeloperoxidase (MPO) mediated reaction. Lucigenin (bis-N-methylacridinium nitrate) also reacts with superoxide in order to generate bioluminescence. However, lucigenin bioluminescence is independent of MPO and it solely relies on phagocyte NADPH oxidase (Phox) in macrophages during chronic inflammation. Together, luminol and lucigenin allow non-invasive visualization and longitudinal assessment of different phagocyte populations across both acute and chronic inflammatory phases. Given the important role of inflammation in a variety of human diseases, we believe this non-invasive imaging method can help investigate the differential roles of neutrophils and macrophages in a variety of pathological conditions.

In vivo Imaging Method to Distinguish Acute and Chronic Inflammation

We describe a non-invasive imaging method for distinguishing inflammatory stages. Systemic delivery of luminol reveals areas of acute inflammation dependent upon MPO activity in neutrophils. In contrast, injection of lucigenin allows for visualization of chronic inflammation dependent upon Phox activity in macrophages.

Inflammation is a fundamental aspect of many human diseases. In this video report, we demonstrate non-invasive bioluminescence imaging techniques that ...

Long Term Chronic Pseudomonas aeruginosa Airway Infection in Mice

A mouse model of chronic airway infection is a key asset in cystic fibrosis (CF) research, although there are a number of concerns regarding the model itself. Early phases of inflammation and infection have been widely studied by using the Pseudomonas aeruginosa agar-beads mouse model, while only few reports have focused on the long-term chronic infection in vivo. The main challenge for long term chronic infection remains the low bacterial burden by P. aeruginosa and the low percentage of infected mice weeks after challenge, indicating that bacterial cells are progressively cleared by the host.
This paper presents a method for obtaining efficient long-term chronic infection in mice. This method is based on the embedding of the P. aeruginosa clinical strains in the agar-beads in vitro, followed by intratracheal instillation in C57Bl/6NCrl mice. Bilateral lung infection is associated with several measurable read-outs including weight loss, mortality, chronic infection, and inflammatory response. The P. aeruginosa RP73 clinical strain was preferred over the PAO1 reference laboratory strain since it resulted in a comparatively lower mortality, more severe lesions, and higher chronic infection. P. aeruginosa colonization may persist in the lung for over three months. Murine lung pathology resembles that of CF patients with advanced chronic pulmonary disease.
This murine model most closely mimics the course of the human disease and can be used both for studies on the pathogenesis and for the evaluation of novel therapies.

Long Term Chronic Pseudomonas aeruginosa Airway Infection in Mice

We describe the agar-beads method to establish persistent long-term chronic Pseudomonas aeruginosa airway infection in the mouse model.

A mouse model of chronic airway infection is a key asset in cystic fibrosis (CF) research, although there are a number of concerns regarding the model ...

Humanized Mouse Model to Study Bacterial Infections Targeting the Microvasculature

Neisseria meningitidis causes a severe, frequently fatal sepsis when it enters the human blood stream. Infection leads to extensive damage of the blood vessels resulting in vascular leak, the development of purpuric rashes and eventual tissue necrosis. Studying the pathogenesis of this infection was previously limited by the human specificity of the bacteria, which makes in vivo models difficult. In this protocol, we describe a humanized model for this infection in which human skin, containing dermal microvessels, is grafted onto immunocompromised mice. These vessels anastomose with the mouse circulation while maintaining their human characteristics. Once introduced into this model, N. meningitidis adhere exclusively to the human vessels, resulting in extensive vascular damage, inflammation and in some cases the development of purpuric rash. This protocol describes the grafting, infection and evaluation steps of this model in the context of N. meningitidis infection. The technique may be applied to numerous human specific pathogens that infect the blood stream.

Neisseria meningitidis is a human specific pathogen that infects blood vessels. In this protocol human microvessels are introduced into a mouse by grafting human skin onto immunocompromised mice. Bacteria adhere extensively to the human vessels, leading to vascular damage and development of the purpuric rash typically observed in human cases.

Neisseria meningitidis causes a severe, frequently fatal sepsis when it enters the human blood stream. Infection leads to extensive damage of the blood ...

Rapid Screening of HIV Reverse Transcriptase and Integrase Inhibitors

Although a number of anti HIV drugs have been approved, there are still problems with toxicity and drug resistance. This demonstrates a need to identify new compounds that can inhibit infection by the common drug resistant HIV-1 strains with minimal toxicity. Here we describe an efficient assay that can be used to rapidly determine the cellular cytotoxicity and efficacy of a compound against WT and mutant viral strains.
The desired target cell line is seeded in a 96-well plate and, after a 24 hr incubation, serially dilutions of the compounds to be tested are added. No further manipulations are necessary for cellular cytotoxicity assays; for anti HIV assays a predetermined amount of either a WT or drug resistant HIV-1 vector that expresses luciferase is added to the cells. Cytotoxicity is measured by using an ATP dependent luminescence assay and the impact of the compounds on infectivity is measured by determining the amount of luciferase in the presence or the absence of the putative inhibitors.
This screening assay takes 4 days to complete and multiple compounds can be screened in parallel. Compounds are screened in triplicate and the data are normalized to the infectivity/ATP levels in absence of target compounds. This technique provides a quick and accurate measurement of the efficacy and toxicity of potential anti HIV compounds.

Here we describe cellular cytotoxicity and single round infectivity assays that allow for the rapid and accurate screening of compounds to determine their cellular cytotoxicity (CC50) and IC50 values against WT and drug resistant HIV-1.

Although a number of anti HIV drugs have been approved, there are still problems with toxicity and drug resistance. This demonstrates a need to identify ...

Mouse Models Of Helicobacter Infection And Gastric Pathologies

Helicobacter pylori is a gastric pathogen that is present in half of the global population and is a significant cause of morbidity and mortality in humans. Several mouse models of gastric Helicobacter infection have been developed to study the molecular and cellular mechanisms whereby H. pylori bacteria colonize the stomach of human hosts and cause disease. Herein, we describe protocols to: 1) prepare bacterial suspensions for the in vivo infection of mice via intragastric gavage; 2) determine bacterial colonization levels in mouse gastric tissues, by polymerase chain reaction (PCR) and viable counting; and 3) assess pathological changes, by histology. To establish Helicobacter infection in mice, specific pathogen-free (SPF) animals are first inoculated with suspensions (containing &#8805;105 colony-forming units, CFUs) of mouse-colonizing strains of either Helicobacter pylori or other gastric Helicobacter spp. from animals, such as Helicobacter felis. At the appropriate time-points post-infection, stomachs are excised and dissected sagittally into two equal tissue fragments, each comprising the antrum and body regions. One of these fragments is then used for either viable counting or DNA extraction, while the other is subjected to histological processing. Bacterial colonization and histopathological changes in the stomach may be assessed routinely in gastric tissue sections stained with Warthin-Starry, Giemsa or Haematoxylin and Eosin (H&#38;E) stains, as appropriate. Additional immunological analyses may also be undertaken by immunohistochemistry or immunofluorescence on mouse gastric tissue sections. The protocols described below are specifically designed to enable the assessment in mice of gastric pathologies resembling those in human-related H. pylori diseases, including inflammation, gland atrophy and lymphoid follicle formation. The inoculum preparation and intragastric gavage protocols may also be adapted to study the pathogenesis of other enteric human pathogens that colonize mice, such as Salmonella Typhimurium or Citrobacter rodentium.

Mouse Models Of Helicobacter Infection And Gastric Pathologies

Mice represent an invaluable in vivo model to study infection and diseases caused by gastrointestinal microorganisms. Here, we describe the methods used to study bacterial colonization and histopathological changes in mouse models of Helicobacter pylori-related disease.

Helicobacter pylori is a gastric pathogen that is present in half of the global population and is a significant cause of morbidity and mortality in ...

Humanized NOD/SCID/IL2r&#947;null (hu-NSG) Mouse Model for HIV Replication and Latency Studies

Ethical regulations and technical challenges for research in human pathology, immunology, and therapeutic development have placed small animal models in high demand. With a close genetic and behavioral resemblance to humans, small animals such as the mouse are good candidates for human disease models, through which human-like symptoms and responses can be recapitulated. Further, the mouse genetic background can be altered to accommodate diverse demands. The NOD/SCID/IL2r&#947;null (NSG) mouse is one of the most widely used immunocompromised mouse strains; it allows engraftment with human hematopoietic stem cells and/or human tissues and the subsequent development of a functional human immune system. This is a critical milestone in understanding the prognosis and pathophysiology of human-specific diseases such as HIV/AIDS and aiding the search for a cure. Herein, we report a detailed protocol for generating a humanized NSG mouse model (hu-NSG) by hematopoietic stem cell transplantation into a radiation-conditioned neonatal NSG mouse. The hu-NSG mouse model shows multi-lineage development of transplanted human stem cells and susceptibility to HIV-1 viral infection. It also recapitulates key biological characteristics in response to combinatorial antiretroviral therapy (cART).

Humanized NOD/SCID/IL2r&amp;#947;&lt;sup&gt;null&lt;/sup&gt; (hu-NSG) Mouse Model for HIV Replication and Latency Studies

This protocol provides a method to establish humanized mice (hu-NSG) via intrahepatic injection of human hematopoietic stem cells into radiation-conditioned neonatal NSG mice. The hu-NSG mouse is susceptible to HIV infection and combinatorial antiretroviral therapy (cART) and serves as a suitable pathophysiological model for HIV replication and latency investigations.

Ethical regulations and technical challenges for research in human pathology, immunology, and therapeutic development have placed small animal models in ...

CRISPR-Cas9-based Genome Engineering to Generate Jurkat Reporter Models for HIV-1 Infection with Selected Proviral Integration Sites

Human immunodeficiency virus (HIV) integrates its proviral DNA non-randomly into the host cell genome at recurrent sites and genomic hotspots. Here we present a detailed protocol for the generation of novel in vitro models for HIV infection with chosen genomic integration sites using CRISPR-Cas9-based genome engineering technology. With this method, a reporter sequence of choice can be integrated into a targeted, chosen genomic locus, reflecting clinically relevant integration sites.
In the protocol, the design of an HIV-derived reporter and choosing of a target site and gRNA sequence are described. A targeting vector with homology arms is constructed and transfected into Jurkat T cells. The reporter sequence is targeted to the selected genomic site by homologous recombination facilitated by a Cas9-mediated double-strand break at the target site. Single-cell clones are generated and screened for targeting events by flow cytometry and PCR. Selected clones are then expanded, and correct targeting is verified by PCR, sequencing, and Southern blotting. Potential off-target events of CRISPR-Cas9-mediated genome engineering are analyzed.
By using this protocol, novel cell culture systems that model HIV infection at clinically relevant integration sites can be generated. Although the generation of single-cell clones and verification of correct reporter sequence integration is time-consuming, the resulting clonal lines are powerful tools to functionally analyze proviral integration site choice.

We present a genome engineering workflow for the generation of new in vitro models for HIV-1 infection that recapitulate proviral integration at selected genomic sites. Targeting of HIV-derived reporters is facilitated by CRISPR-Cas9-mediated, site-specific genome manipulation. Detailed protocols for single-cell clone generation, screening, and correct targeting verification are provided.

Human immunodeficiency virus (HIV) integrates its proviral DNA non-randomly into the host cell genome at recurrent sites and genomic hotspots. Here we ...

Establishment of the Dual Humanized TK-NOG Mouse Model for HIV-associated Liver Pathogenesis

Despite the increased life expectancy of patients infected with human immunodeficiency virus-1 (HIV-1), liver disease has emerged as a common cause of their morbidity. The liver immunopathology caused by HIV-1 remains elusive. Small xenograft animal models with human hepatocytes and human immune system can recapitulate the human biology of the disease&#39;s pathogenesis. Herein, a protocol is described to establish a dual humanized mouse model through human hepatocytes and CD34+ hematopoietic stem/progenitor cells (HSPCs) transplantation, to study liver immunopathology as observed in HIV-infected patients. To achieve dual reconstitution, male TK-NOG (NOD.Cg-Prkdcscid Il2rgtm1Sug Tg(Alb-TK)7-2/ShiJic) mice are intraperitoneally injected with ganciclovir (GCV) doses to eliminate mouse transgenic liver cells, and with treosulfan for nonmyeloablative conditioning, both of which facilitate human hepatocyte (HEP) engraftment and human immune system (HIS) development. Human albumin (ALB) levels are evaluated for liver engraftment, and the presence of human immune cells in blood detected by flow cytometry confirms the establishment of human immune system. The model developed using the protocol described here resembles multiple components of liver damage from HIV-1 infection. Its establishment could prove to be essential for studies of hepatitis virus co-infection and for the evaluation of antiviral and antiretroviral drugs.

This protocol provides a reliable method to establish humanized mice with both human immune system and liver cells. Dual reconstituted immunodeficient mice achieved via intrasplenic injection of human hepatocytes and CD34+ hematopoietic stem cells are susceptible to human immunodeficiency virus-1 infection and recapitulate liver damage as observed in HIV-infected patients.

Despite the increased life expectancy of patients infected with human immunodeficiency virus-1 (HIV-1), liver disease has emerged as a common cause of ...