The authors would like to acknowledge the receipt of both the Pediatric Orthopaedic Society of North America Biomet Spine Grant and the National Institutes of Health Clinical and Translational Science Institute KL2 Grant, and the HH Lee Surgical Research Grant as major funding sources for these experiments.

All animals were handled in strict accordance with good animal practice as defined in the federal regulations as set forth in the Animal Welfare Act (AWA), the 1996 Guide for the Care and Use of Laboratory Animals, PHS Policy for the Humane Care and Use of Laboratory Animals, as well as the institution&#8217;s policies and procedures as set forth in the Animal Care and Use Training Manual, and all animal work was approved by the University of California Los Angeles Chancellor&#8217;s Animal Research Committee (ARC).
1. S. aureus bioluminescent strain choice
<ol>
	<li>Use the bioluminescent S. aureus strain Xen36 as the inoculum of interest. 
	NOTE: This strain was derived from the parental strain S. aureus ATCC-49525, which is a clinical isolate from a septic patient. S. aureus Xen36 uniquely utilizes a luxABCDE operon, which is optimized and integrated into the host&#8217;s native plasmid.19 As a result, the Xen36 strain is capable of producing a blue-green bioluminescent light with a peak wavelength emission of 490 nm. This emission signal is only produced by living metabolically active bacterial organisms.</li>
</ol>
2. Preparation of S. aureus for inoculation
<ol>
	<li>Add 200 &#956;g/mL kanamycin to Luria Broth plus 1.5% agar to isolate S. aureus Xen36 from potential contaminants, utilizing the kanamycin resistance gene linked to the lux operon19.</li>
	<li>Streak S. aureus Xen36 bacteria onto tryptic soy agar plates (tryptic soy broth [TSB] plus 1.5% agar) and incubate at 37 &#176;C for 12-16 h.</li>
	<li>Isolate single colonies of S. aureus Xen36 and individually culture in TSB for 12-16 h at 37 &#176;C in a shaking incubator (200 rpm).</li>
	<li>Dilute resultant culture at a 1:50 ratio.</li>
	<li>Culture for additional 2 h at 37 &#176;C to isolate midlogarithmic phase bacteria.</li>
	<li>Pellet, resuspend, and wash bacteria in phosphate buffered saline (PBS) three times.</li>
	<li>Measure the absorbance at 600 nm. The ideal OD600 is between 0.700 and 0.750 which corresponds to 4x105 CFU/mL. Perform serial dilutions to achieve desired bacterial inoculum (1 x 103&#160; CFU/2 &#181;L). 
	NOTE: The optimal concentration of Xen36 for the establishment of a chronic infection was found to be 1 x 103 CFU. Lower dosing of bacteria was cleared by the host immune system and higher dosing caused wound breakdown. Wound breakdown does not differentiate between a deep implant infection and a superficial wound infection and is therefore avoided in this model (Figure 1)20.</li>
</ol>
3. Mice
<ol>
	<li>Use 12-week old male C57BL/6J wild-type mice.</li>
	<li>House mice in cages with a maximum of 4 at a time.</li>
	<li>Keep water available at all times. Maintain a 12-hour light/dark cycle and do not perform experimentation during the dark phase of the cycle.</li>
	<li>Use alfalfa-free chow for feeding due to potential interference with fluorescent signaling.</li>
	<li>Have research or veterinary staff assess mice daily to ensure the well-being of the animals throughout the entirety of the experiment.</li>
</ol>
4. Mouse surgical procedures
<ol>
	<li>Induce anesthesia by placing mice in an isoflurane (2%) chamber for approximately 5 minutes. Confirm appropriate depth of anesthesia by monitoring respirations to remain rhythmic and slower than when awake and not changing in response to noxious stimuli (e.g., surgical manipulation, toe pinch).</li>
	<li>Transfer anesthetized mice to a preparation station and remove hair from the sacrum to the upper thoracic spine with rodent clippers.</li>
	<li>Clean and sterilize the skin with triple washes of alternating betadine solution and isopropyl alcohol.</li>
	<li>Transfer anesthetized and sterilized mice in the prone position to a sterile surgical bed maintaining anesthesia with administration of inhaled isoflurane (2%) via nose cone.</li>
	<li>Maximally flex the hips and identify the position of the knee at the level of the spine to approximate the lumbar 4 vertebral body.</li>
	<li>Make a longitudinal 2 cm incision through skin with a 15-blade surgical scalpel.</li>
	<li>Palpate the spinous processes to confirm midline and continue the incision down to bone.</li>
	<li>Dissect subperiosteally on the right side of the L4 spinous process, extending laterally to the transverse process.</li>
	<li>Pass an absorbable braided suture size 5-0 cephalad and caudad to the L4 body through the fascia and leave open, in preparation for future closure.</li>
	<li>Using a 25 G spinal needle, ream the spinous process of L4 using a 25 G spinal needle and insert a 0.1 mm diameter, 1 cm long &#8220;L-shaped&#8221; surgical grade stainless-steel implant along the lamina with the long arm laying cephalad.</li>
	<li>Inoculate the implant with 1 x 103 CFUs/2 &#181;L bioluminescent S. aureus Xen36, taking care to ensure all solution contacts the implant.</li>
	<li>Wait approximately 10 seconds before tying the previously passed absorbable suture following inoculation to ensure containment of inoculum on the implant.</li>
	<li>Close skin in running fashion with absorbable suture.</li>
	<li>Administer pain medicine via subcutaneous injection of buprenorphine (0.1 mg/kg) immediately postop and then every 12 hours for 3 days thereafter.</li>
	<li>Recover mice on a heating pad and monitor for return to normal activity.</li>
	<li>Obtain postoperative radiographs to confirm appropriate placement of implant.</li>
</ol>
5. Longitudinal In vivo bioluminescence imaging to measure bacterial burden
<ol>
	<li>Anesthetize mice with inhaled isoflurane (2%). Confirm appropriate depth of anesthesia by monitoring respirations to remain rhythmic and slower than when awake and not changing in response to noxious stimuli (e.g., surgical manipulation, toe pinch).</li>
	<li>Remove hair from the sacrum to the upper thoracic spine with rodent clippers.</li>
	<li>Load mice onto field of view of bioluminescent imaging platform to perform in vivo bioluminescence imaging (BLI)19.</li>
	<li>Capture bioluminescent signal over a 5 min acquisition time. Utilize large binning settings with a 15 cm field of view (B).</li>
	<li>Repeat steps 5.1-5.4 on postoperative days 0, 1, 3, 5, 7, 10, 14, 18, 21, 25, 28, and 35 (or other days based on specific experimental design) to monitor bacterial burden.</li>
	<li>Present BLI data via color scale and overlay on a grayscale photograph. Isolate a standard ovoid region of interest (ROI) using BLI software to quantify BLI in total flux (photons per second) or mean maximum flux (photons/second/centimeter2/steradian).</li>
</ol>
6. Quantify bacteria adherent to implants and surrounding tissue
<ol>
	<li>Euthanize mice on POD 35 or an alternative post-operative date of choice with exposure to carbon dioxide in accordance with AVMA Guidelines. Confirm euthanasia with secondary cervical dislocation.</li>
	<li>Sterilize the dorsal skin according to Step 4.3 and position the mouse prone on a sterile surgical field.</li>
	<li>Sharply incise the previous incision using a 15-blade surgical scalpel.</li>
	<li>Use sterile scissors to bluntly dissect to the L4 spinous process and identify the surgical implant.</li>
	<li>Use a needle driver to gently twist and remove the implant from its position in the L4 spinous process.</li>
	<li>Using sterile forceps and scissors, harvest approximately 0.1 g of spinous process bone and soft tissue immediately surrounding the surgical implant and place in 1 mL of PBS in small conical rhino tube with 4 sharp homogenizing beads.</li>
	<li>Record weight of soft tissue by weighing conical tube before and after harvest.</li>
	<li>Place the implant in 0.5 mL of 0.3% Tween-80 in TSB and sonicate for 15 min.</li>
	<li>Vortex the resulting implant suspension for 2 min and culture overnight for 12-16 h.</li>
	<li>Homogenize the soft tissue and spinous processes previously placed in 1 ml PBS surrounding the implant using homogenizer.</li>
	<li>Vortex the resulting soft tissue suspension for 5 min and culture overnight for 12-16 h.</li>
	<li>After overnight culture, count CFU from the implant and surrounding tissues, respectively. Express value as total CFU/g harvested for soft tissue and CFU/mL for sonicated implant.</li>
</ol>

<ol>
	<li>Verdrengh, M., Tarkowski, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Role+of+neutrophils+in+experimental+septicemia+and+septic+arthritis+induced+by+Staphylococcus+aureus.">Role of neutrophils in experimental septicemia and septic arthritis induced by Staphylococcus aureus.</a> Infection and Immunity. 65 (7), 2517-2521 (1997).</li><li>Fang, A., Hu, S. S., Endres, N., Bradford, D. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Risk+factors+for+infection+after+spinal+surgery.">Risk factors for infection after spinal surgery.</a> Spine. 30 (12), 1460-1465 (2005).</li><li>Levi, A. D., Dickman, C. A., Sonntag, V. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Management+of+postoperative+infections+after+spinal+instrumentation.">Management of postoperative infections after spinal instrumentation.</a> Journal of Neurosurgery. 86 (6), 975-980 (1997).</li><li>Weinstein, M. A., McCabe, J. P., Cammisa, F. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Postoperative+spinal+wound+infection:+a+review+of+2,391+consecutive+index+procedures.">Postoperative spinal wound infection: a review of 2,391 consecutive index procedures.</a> Journal of Spinal Disorders. 13 (5), 422-426 (2000).</li><li>Picada, 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=Postoperative+deep+wound+infection+in+adults+after+posterior+lumbosacral+spine+fusion+with+instrumentation:+incidence+and+management.">Postoperative deep wound infection in adults after posterior lumbosacral spine fusion with instrumentation: incidence and management.</a> Journal of Spinal Disorders. 13 (1), 42-45 (2000).</li><li>Smith, J. 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=Rates+of+infection+after+spine+surgery+based+on+108,419+procedures:+a+report+from+the+Scoliosis+Research+Society+Morbidity+and+Mortality+Committee.">Rates of infection after spine surgery based on 108,419 procedures: a report from the Scoliosis Research Society Morbidity and Mortality Committee.</a> Spine. 36 (7), 556-563 (2011).</li><li>Abbey, D. M., Turner, D. M., Warson, J. S., Wirt, T. C., Scalley, R. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Treatment+of+postoperative+wound+infections+following+spinal+fusion+with+instrumentation.">Treatment of postoperative wound infections following spinal fusion with instrumentation.</a> Journal of Spinal Disorders. 8 (4), 278-283 (1995).</li><li>Silber, J. 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=Management+of+postprocedural+discitis.">Management of postprocedural discitis.</a> Spine Journal. 2 (4), 279-287 (2002).</li><li>Pappou, I. P., Papadopoulos, E. C., Sama, A. A., Girardi, F. P., Cammisa, F. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Postoperative+infections+in+interbody+fusion+for+degenerative+spinal+disease.">Postoperative infections in interbody fusion for degenerative spinal disease.</a> Clinical Orthopaedics and Related Research. 444, 120-128 (2006).</li><li>Sampedro, M. 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=A+biofilm+approach+to+detect+bacteria+on+removed+spinal+implants.">A biofilm approach to detect bacteria on removed spinal implants.</a> Spine. 35 (12), 1218-1224 (2010).</li><li>Pull ter Gunne, A. F., Mohamed, A. S., Skolasky, R. L., van Laarhoven, C. J., Cohen, D. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+presentation,+incidence,+etiology,+and+treatment+of+surgical+site+infections+after+spinal+surgery.">The presentation, incidence, etiology, and treatment of surgical site infections after spinal surgery.</a> Spine. 35 (13), 1323-1328 (2010).</li><li>Olsen, 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=Risk+factors+for+surgical+site+infection+in+spinal+surgery.">Risk factors for surgical site infection in spinal surgery.</a> Journal of Neurosurgery. 98, 149-155 (2003).</li><li>Ofluoglu, E. 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=Implant-related+infection+model+in+rat+spine.">Implant-related infection model in rat spine.</a> Archives of Orthopaedic and Trauma Surgery. 127 (5), 391-396 (2007).</li><li>Guiboux, J. 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=The+role+of+prophylactic+antibiotics+in+spinal+instrumentation.+A+rabbit+model.">The role of prophylactic antibiotics in spinal instrumentation. A rabbit model.</a> Spine. 23 (6), 653-656 (1998).</li><li>Stavrakis, A. 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=Current+Animal+Models+of+Postoperative+Spine+Infection+and+Potential+Future+Advances.">Current Animal Models of Postoperative Spine Infection and Potential Future Advances.</a> Frontiers in Medicine (Lausanne). 2, 34 (2015).</li><li>Pribaz, J. 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=Mouse+model+of+chronic+post-arthroplasty+infection:+noninvasive+in+vivo+bioluminescence+imaging+to+monitor+bacterial+burden+for+long-term+study.">Mouse model of chronic post-arthroplasty infection: noninvasive in vivo bioluminescence imaging to monitor bacterial burden for long-term study.</a> Journal of Orthopaedic Research. 30 (3), 335-340 (2012).</li><li>Bernthal, N. 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+mouse+model+of+post-arthroplasty+Staphylococcus+aureus+joint+infection+to+evaluate+in+vivo+the+efficacy+of+antimicrobial+implant+coatings.">A mouse model of post-arthroplasty Staphylococcus aureus joint infection to evaluate in vivo the efficacy of antimicrobial implant coatings.</a> PLoS One. 5 (9), 12580 (2010).</li><li>Niska, J. 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=Monitoring+bacterial+burden,+inflammation+and+bone+damage+longitudinally+using+optical+and+muCT+imaging+in+an+orthopaedic+implant+infection+in+mice.">Monitoring bacterial burden, inflammation and bone damage longitudinally using optical and muCT imaging in an orthopaedic implant infection in mice.</a> PLoS One. 7 (10), 47397 (2012).</li><li>Francis, K. 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=Monitoring+bioluminescent+Staphylococcus+aureus+infections+in+living+mice+using+a+novel+luxABCDE+construct.">Monitoring bioluminescent Staphylococcus aureus infections in living mice using a novel luxABCDE construct.</a> Infection and Immunity. 68 (6), 3594-3600 (2000).</li><li>Dworsky, E. 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=Novel+in+vivo+mouse+model+of+implant+related+spine+infection.">Novel in vivo mouse model of implant related spine infection.</a> Journal of Orthopaedic Research. 35 (1), 193-199 (2017).</li><li>Hegde, S. 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=Activity+of+telavancin+against+heterogeneous+vancomycin-intermediate+Staphylococcus+aureus+(hVISA)+in+vitro+and+in+an+in+vivo+mouse+model+of+bacteraemia.">Activity of telavancin against heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) in vitro and in an in vivo mouse model of bacteraemia.</a> Journal of Antimicrobial Chemotherapy. 65 (4), 725-728 (2010).</li><li>Crandon, J. L., Kuti, J. L., Nicolau, D. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparative+efficacies+of+human+simulated+exposures+of+telavancin+and+vancomycin+against+methicillin-resistant+Staphylococcus+aureus+with+a+range+of+vancomycin+MICs+in+a+murine+pneumonia+model.">Comparative efficacies of human simulated exposures of telavancin and vancomycin against methicillin-resistant Staphylococcus aureus with a range of vancomycin MICs in a murine pneumonia model.</a> Antimicrobial Agents and Chemotherapy. 54 (12), 5115-5119 (2010).</li><li>Reyes, 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=Efficacy+of+telavancin+in+a+murine+model+of+bacteraemia+induced+by+methicillin-resistant+Staphylococcus+aureus.">Efficacy of telavancin in a murine model of bacteraemia induced by methicillin-resistant Staphylococcus aureus.</a> Journal of Antimicrobial Chemotherapy. 58 (2), 462-465 (2006).</li><li>Sakoulas, G., Eliopoulos, G. 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The authors have no conflicts of interest to disclose.

Implant related infections in the spine portend poor outcomes for patients1,2,3,4,5. Unlike many other areas in the body, infected hardware in the spine frequently cannot be removed due to the risk of instability and neurologic compromise. This unique challenge in the setting of biofilm bacteria resistant to systemic antibiotic therapy necessitate novel approa...

An erratum was issued for:&#160;<a href="https://www.jove.com/t/60560">In vivo Mouse Model of Spinal Implant Infection</a>. The Authors section was updated from:
Benjamin V. Kelley1 
Stephen D. Zoller1 
Danielle Greig1 
Kellyn Hori1 
Nicolas Cevallos1 
Chad Ishmael1 
Peter Hsiue1 
Rishi Trikha1 
Troy Sekimura2 
Thomas Olson2 
Ameen Chaudry2 
Michael M. Le2 
Anthony A. Scaduto1 
Kevin P. Francis1 
Nicholas M. Bernthal1 
1Department of Orthopaedic Surgery, University of California Los Angeles 
2David Geffen School of Medicine, University of California Los Angeles
to:
Benjamin V. Kelley1 
Christopher Hamad1 
Stephen D. Zoller1 
Danielle Greig1 
Zeinab Mamouei1 
Rene Chun1 
Kellyn Hori1 
Nicolas Cevallos1 
Chad Ishmael1 
Peter Hsiue1 
Rishi Trikha1 
Troy Sekimura2 
Brandon Gettleman3 
Autreen Golzar2 
Adrian Lin2 
Thomas Olson2 
Ameen Chaudry2 
Michael M. Le2 
Anthony A. Scaduto1 
Kevin P. Francis1 
Nicholas M. Bernthal1 
1Department of Orthopaedic Surgery, University of California Los Angeles 
2David Geffen School of Medicine, University of California Los Angeles 
3University of South Carolina School of Medicine, University of South Carolina

An erratum was issued for:&#160;<a href="https://www.jove.com/t/60560">In vivo Mouse Model of Spinal Implant Infection</a>. The Authors section was updated.

Erratum: In vivo Mouse Model of Spinal Implant Infection

The purpose of this method is to describe a novel mouse model of spinal implant infection (SII). This model was designed to provide an inexpensive and accurate tool to flexibly assess the effect of host, pathogen, and/or implant variables in vivo. Testing potential therapeutics and treatment strategies for spinal implant infections in this model is aimed at guiding research development prior to application in larger animal models and clinical trials.
Implant related infection after spine surgery is a devastating complication and unfortunately occurs in approximately 3&#8211;8% of patients undergoing elective spine surgery1,2,3,4,5 and up to 65% of patients undergoing multilevel or revision surgery6. Treatment of spinal implant infections often requires multiple hospitalizations, multiple surgeries, and prolonged antibiotic therapy. SIIs portend poor patient outcomes including neurological compromise, disability, and an increased risk of mortality. Management of SII is extremely expensive, costing upwards of $900,000 per patient7.
Staphylococcus aureus is the most common virulent pathogen of SII8,9,10,11. Bacteria can seed the hardware directly during surgery, through the wound during the postoperative period, or later via hematogenous spread. In the presence of metal implants, S. aureus form biofilm that protects the bacteria from antibiotic therapy and immune cells. While removal of infected hardware may help effectively eradicate an infection, this is frequently not feasible in the spine without causing destabilization and risking neurologic compromise12.
In the absence of explanting infected hardware, novel approaches are needed to prevent, detect, and treat SII. Historically, there have been limited animal models of SII to efficiently assess the safety and efficacy of novel therapies. Previous animal models of SII require large numbers of animals and collection of data points requiring euthanasia including colony counting, histology, and culture13,14,15. Lacking longitudinal in vivo monitoring, these models only provide one data point per animal and are therefore expensive and inefficient.
Previous work studying a mouse model of knee arthroplasty infection established the value and accuracy of noninvasive in vivo optical imaging to longitudinally monitor infection burden16. The detection of bioluminescence allows bacterial burden to be quantified over a longitudinal time course in a single animal humanely, accurately, and efficiently. Moreover, prior studies have demonstrated a high correlation between in vivo bioluminescence and CFUs adherent to implants17. The capacity to track infection over time, has led to a more nuanced understanding of implant related infection. In addition, monitoring longitudinal infection in this way, has allowed the effectiveness of antibiotic therapy and novel antimicrobials to be accurately assessed16,17,18.
Leveraging these tools, we developed and validated a model of postoperative spinal implant infection. In the method presented, we utilize an inoculum of bioluminescent S. aureus Xen36 to establish an in vivo mouse model of SII to longitudinally monitor bacterial burden16,17,18. This novel model provides a valuable tool to efficiently test potential detection, prevention, and treatment strategies for SII prior to their application in larger animal models and clinical trials.

<table>
	<tbody>
		<tr>
			<td>Analytical Balance ME104</td>
			<td>Mettler Toledo</td>
			<td>30029067</td>
			<td>120 g capacity, 0.1 mg readability, backlit LCD, internal adjustment, metal base</td>
		</tr>
		<tr>
			<td>BD Bacto Tryptic Soy Broth</td>
			<td>Becton Dickinson (BD)</td>
			<td>BD 211825</td>
			<td>BD Bacto Tryptic Soy Broth (Soybean-Casein Digest Medium)</td>
		</tr>
		<tr>
			<td>Biomate 3S UV-VIS Spectrophotometer</td>
			<td>Thermo Scientific</td>
			<td>840-208300</td>
			<td>Spectrophotometer; Thermo Scientific; BioMate 3S; Six-position cell holder; Spectral bandwidth: 1.8nm; Long-life xenon lamp; Store up to 40 test methods; 16L x 13W x 9 in. H; 19 lb.; 100/240V US line cord</td>
		</tr>
		<tr>
			<td>Bioshield 720+ swinging bucket rotor</td>
			<td>Thermo Scientific</td>
			<td>75003183</td>
			<td>Rotor, Swinging bucket; Thermo Scientific; BIOShield 720 high speed; Capacity: 4 x 180mL (0.72L); Angle: 90 deg. ; Max. speed/RCF: 6300rpm/7188 x g; Max. radius: 16.2cm</td>
		</tr>
		<tr>
			<td>Branson Ultrasonics 2510R-MTH (Sonicator)</td>
			<td>Branson Ultrasonics</td>
			<td>CPX952217R</td>
			<td>*similar model, our model is discontinued* Branson Ultrasonics MH Series Heated Ultrasonic Cleaning Bath, 120V, 0.75 gal</td>
		</tr>
		<tr>
			<td>Bullet Blender Storm Homogenizer</td>
			<td>Next Advance</td>
			<td>BBY24M</td>
			<td>The Bullet Blender Storm is the most powerful member of the Bullet Blender family. Homogenize up to 24 of your toughest samples (mouse femur, skin, cartilage, tumor, etc.) in just minutes. Air cooling&#8482; minimizes sample heat up. Uses 1.5ml screw-cap RINO&#174; tubes or snap-cap Eppendorf&#174; Safe-lock&#8482; tubes.</td>
		</tr>
		<tr>
			<td>Germinator 500</td>
			<td>Electron Microscopy Sciences</td>
			<td>66118-10</td>
			<td>The Germinator 500 is designed to decontaminate metal micro-dissecting instruments only. It is to be 
			used exclusively for research purposes. The Germinator 500 should not be used as a substitute for 
			traditional methods of terminal sterilization. Effective sterilization cannot be assured due to lack of routine 
			sterilization-efficacy monitoring methods for glass bead sterilization. The Germinator 500 has been 
			designed and built to pass the Validation of Dry Sterilizer Spore Suspension Test: USP XXIII, Part 1211.</td>
		</tr>
		<tr>
			<td>Heracell 150i CO2 Incubator</td>
			<td>Thermo Scientific</td>
			<td>51026282</td>
			<td>Single 150L</td>
		</tr>
		<tr>
			<td>IVIS Lumina X5 Imaging System</td>
			<td>Perkin Elmer</td>
			<td>CLS148590</td>
			<td>The IVIS Lumina X5 high-throughput 2D optical imaging system combines high-sensitivity bioluminescence and fluorescence with high-resolution x-ray into a compact system that fits on your benchtop. With an expanded 5 mouse field of view for 2D optical imaging plus our unique line of accessories to accelerate setup and labeling, it has never been easier or faster to get robust data&#8212;and answers&#8212;on anatomical and molecular aspects of disease.</td>
		</tr>
		<tr>
			<td>MAXQ 4450 Digtial Incubating Bench Shaker</td>
			<td>Thermo Scientific</td>
			<td>SHKE4450</td>
			<td>Shaker, Incubated; Thermo Scientific; Digital; MaxQ 4450; Speed 15 to 500rpm +/-1rpm; 5 deg. C above ambient to 80 deg. C; 120V 50/60Hz</td>
		</tr>
		<tr>
			<td>PBS, Phosphate Buffered Saline</td>
			<td>Fisher Bioreagents</td>
			<td>BP24384</td>
			<td>PBS, Phosphate Buffered Saline, 1X Solution, pH 7.4</td>
		</tr>
		<tr>
			<td>Sorvall Legend Micro 21 Centrifuge, Ventilated</td>
			<td>Thermo Scientific</td>
			<td>75002436</td>
			<td>24 x 1.5/2.0mL rotor with ClickSeal biocontainment lid</td>
		</tr>
		<tr>
			<td>SORVALL LEGEND X1R 120V Centrifuge</td>
			<td>Thermo Scientific</td>
			<td>75004261</td>
			<td>Centrifuge, Benchtop; Thermo Scientific; Sorvall Legend X1R (Refrigerated), 1L capacity; Max. Speed/RCF 15,200rpm/25,830 x g; CFC-free cooling -10C to +40C; 120V 60Hz</td>
		</tr>
		<tr>
			<td>Staphylococcus aureus - Xen36</td>
			<td>Perkin Elmer</td>
			<td>119243</td>
			<td>Staphylococcus aureus - Xen36 bioluminescent pathogenic bacteria for in vivo and in vitro drug discovery. This product was derived from a parental strain from the American Type Culture Collection, used under license. Staph. aureus-Xen36 possesses a stable copy of the Photorhabdus luminescens lux operon on the native plasmid.</td>
		</tr>
		<tr>
			<td>TUTTNAUER AUTOCLAVE 2540E 120V</td>
			<td>Heidolph Tuttnauer</td>
			<td>23210401</td>
			<td>Sterilizer, Benchtop; Heidolph; Tuttnauer; Model 2540E; Self-contained design with refillable reservoir controls water purity for sterilization; 120V 50/60Hz; 1400w. With electronic controls</td>
		</tr>
		<tr>
			<td>Tween 80</td>
			<td>Fisher Bioreagents</td>
			<td>BP338-500</td>
			<td>Tween 80, Fisher BioReagents, Non-ionic detergent for selective protein extraction</td>
		</tr>
		<tr>
			<td>Vortex mixer VX-200</td>
			<td>Labnet Internation</td>
			<td>S0200</td>
			<td>120V touch or continuous mixer, 230V: 0 - 2,850 rpm,120V: 0 - 3,400 rpm</td>
		</tr>
		<tr>
			<td>0.9% Sodium Chloride</td>
			<td>Pfizer Injectables/Hospira</td>
			<td>00409-4888-10</td>
			<td>0.9% Sodium Chloride Injection, USP</td>
		</tr>
	</tbody>
</table>

in vivo mouse model of spinal implant infection

Spine implant infections portend poor outcomes as diagnosis is challenging and surgical eradication is at odds with mechanical spinal stability. The purpose of this method is to describe a novel mouse model of spinal implant infection (SII) that was created to provide an inexpensive, rapid, and accurate in vivo tool to test potential therapeutics and treatment strategies for spinal implant infections.
In this method, we present a model of posterior-approach spinal surgery in which a stainless-steel k-wire is transfixed into the L4 spinous process of 12-week old C57BL/6J wild-type mice and inoculated with 1 x 103 CFU of a bioluminescent strain of Staphylococcus aureus Xen36 bacteria. Mice are then longitudinally imaged for bioluminescence in vivo on post-operative days 0, 1, 3, 5, 7, 10, 14, 18, 21, 25, 28, and 35. Bioluminescence imaging (BLI) signals from a standardized field of view are quantified to measure in vivo bacterial burden.
To quantify bacteria adhering to implants and peri-implant tissue, mice are euthanized and the implant and surrounding soft tissue are harvested. Bacteria are detached from the implant by sonication, cultured overnight and then colony forming units (CFUs) are counted. The results acquired from this method include longitudinal bacterial counts as measured by in vivo S. aureus bioluminescence (mean maximum flux) and CFU counts following euthanasia.
While prior animal models of instrumented spine infection have involved invasive, ex vivo tissue analysis, the mouse model of SII presented in this paper leverages noninvasive, real time in vivo optical imaging of bioluminescent bacteria to replace static tissue study. Applications of the model are broad and may include utilizing alternative bioluminescent bacterial strains, incorporating other types of genetically engineered mice to contemporaneously study host immune response, and evaluating current or investigating new diagnostic and therapeutic modalities such as antibiotics or implant coatings.

The procedure presented here was used to assess the efficacy of antibiotic regimens in an in vivo mouse model of SII. Specifically, the efficacy of combination vancomycin and rifampin antibiotic therapy was compared to vancomycin monotherapy and untreated infected controls.
Prior to surgery, mice were randomized to either combination therapy, monotherapy, or infected control. A statistical power analysis was performed to calculate sample size. Anticipated means of mean maximum flux 1 x 10...

Watch this Scientific Journal Video about In Vivo Mouse Model of Spinal Implant Infection at JoVE.com

In Vivo Mouse Model of Spinal Implant Infection

The protocol describes a novel in vivo mouse model of spinal implant infection where a stainless-steel k-wire implant is infected with bioluminescent Staphylococcus aureus Xen36. Bacterial burden is monitored longitudinally with bioluminescent imaging and confirmed with colony forming unit counts after euthanasia.

Spine implant infections portend poor outcomes as diagnosis is challenging and surgical eradication is at odds with mechanical spinal stability. The ...

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Research

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2.2K Views.  University of California Los Angeles. The protocol describes a novel in vivo mouse model of spinal implant infection where a stainless-steel k-wire implant is infected with bioluminescent Staphylococcus aureus Xen36. Bacterial burden is monitored longitudinally with bioluminescent imaging and confirmed with colony forming unit counts after euthanasia.

Video: In Vivo Mouse Model of Spinal Implant Infection

Ex Vivo Infection of Live Tissue with Oncolytic Viruses

Oncolytic Viruses (OVs) are novel therapeutics that selectively replicate in and kill tumor cells1. Several clinical trials evaluating the effectiveness of a variety of oncolytic platforms including HSV, Reovirus, and Vaccinia OVs as treatment for cancer are currently underway2-5. One key characteristic of oncolytic viruses is that they can be genetically modified to express reporter transgenes which makes it possible to visualize the infection of tissues by microscopy or bio-luminescence imaging6,7. This offers a unique advantage since it is possible to infect tissues from patients ex vivo prior to therapy in order to ascertain the likelihood of successful oncolytic virotherapy8. To this end, it is critical to appropriately sample tissue to compensate for tissue heterogeneity and assess tissue viability, particularly prior to infection9. It is also important to follow viral replication using reporter transgenes if expressed by the oncolytic platform as well as by direct titration of tissues following homogenization in order to discriminate between abortive and productive infection. The object of this protocol is to address these issues and herein describes 1. The sampling and preparation of tumor tissue for cell culture 2. The assessment of tissue viability using the metabolic dye alamar blue 3. Ex vivo infection of cultured tissues with vaccinia virus expressing either GFP or firefly luciferase 4. Detection of transgene expression by fluorescence microscopy or using an In Vivo Imaging System (IVIS) 5. Quantification of virus by plaque assay. This comprehensive method presents several advantages including ease of tissue processing, compensation for tissue heterogeneity, control of tissue viability, and discrimination between abortive infection and bone fide viral replication.

Ex Vivo Infection of Live Tissue with Oncolytic Viruses

Oncolytic viruses are promising for cancer therapeutics. The ability to ascertain the infectability of live tissue specimens obtained from patients prior to treatment is a unique advantage of this therapeutic approach. This protocol describes how to process tissues for ex vivo infection with oncolytic virus and subsequent viral quantification.

Oncolytic Viruses (OVs) are novel therapeutics that selectively replicate in and kill tumor cells1. Several clinical trials evaluating the effectiveness ...

Longitudinal Evaluation of Mouse Hind Limb Bone Loss After Spinal Cord Injury using Novel, in vivo, Methodology

Spinal cord injury (SCI) is often accompanied by osteoporosis in the sublesional regions of the pelvis and lower extremities, leading to a higher frequency of fractures 1. As these fractures often occur in regions that have lost normal sensory function, the patient is at a greater risk of fracture-dependent pathologies, including death. SCI-dependent loss in both bone mineral density (BMD, grams/cm2) and bone mineral content (BMC, grams) has been attributed to mechanical disuse 2, aberrant neuronal signaling 3 and hormonal changes 4. The use of rodent models of SCI-induced osteoporosis can provide invaluable information regarding the mechanisms underlying the development of osteoporosis following SCI as well as a test environment for the generation of new therapies 5-7 (and reviewed in 8). Mouse models of SCI are of great interest as they permit a reductionist approach to mechanism-based assessment through the use of null and transgenic mice. While such models have provided important data, there is still a need for minimally-invasive, reliable, reproducible, and quantifiable methods in determining the extent of bone loss following SCI, particularly over time and within the same cohort of experimental animals, to improve diagnosis, treatment methods, and/or prevention of SCI-induced osteoporosis.
An ideal method for measuring bone density in rodents would allow multiple, sequential (over time) exposures to low-levels of X-ray radiation. This study describes the use of a new whole-animal scanner, the IVIS Lumina XR (Caliper Instruments) that can be used to provide low-energy (1-3 milligray (mGy)) high-resolution, high-magnification X-ray images of mouse hind limb bones over time following SCI. Significant bone density loss was seen in the tibiae of mice by 10 days post-spinal transection when compared to uninjured, age-matched control (na&iuml;ve) mice (13% decrease, p&lt;0.0005). Loss of bone density in the distal femur was also detectable by day 10 post-SCI, while a loss of density in the proximal femur was not detectable until 40 days post injury (7% decrease, p&lt;0.05). SCI-dependent loss of mouse femur density was confirmed post-mortem through the use of Dual-energy X-ray Absorptiometry (DXA), the current "gold standard" for bone density measurements. We detect a 12% loss of BMC in the femurs of mice at 40 days post-SCI using the IVIS Lumina XR. This compares favorably with a previously reported BMC loss of 13.5% by Picard and colleagues who used DXA analysis on mouse femurs post-mortem 30 days post-SCI 9. Our results suggest that the IVIS Lumina XR provides a novel, high-resolution/high-magnification method for performing long-term, longitudinal measurements of hind limb bone density in the mouse following SCI.

Longitudinal Evaluation of Mouse Hind Limb Bone Loss After Spinal Cord Injury using Novel, in vivo, Methodology

A longitudinal examination of bone loss in the femurs and tibiae of adult mice was performed following spinal cord injury using sequential low-dose X-ray scans. Tibia bone loss was detected throughout the study, while bone loss in the femur was not detected until 40 days post injury.

Spinal cord injury (SCI) is often accompanied by osteoporosis in the sublesional regions of the pelvis and lower extremities, leading to a higher ...

Clinical Testing and Spinal Cord Removal in a Mouse Model for Amyotrophic Lateral Sclerosis (ALS)

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder resulting in progressive degeneration of motoneurons. Peak of onset is around 60 years for the sporadic disease and around 50 years for the familial disease. Due to its progressive course, 50% of the patients die within 30 months of symptom onset. In order to evaluate novel treatment options for this disease, genetic mouse models of ALS have been generated based on human familial mutations in the SOD gene, such as the SOD1 (G93A) mutation. Most important aspects that have to be evaluated in the model are overall survival, clinical course and motor function. Here, we demonstrate the clinical evaluation, show the conduction of two behavioural motor tests and provide quantitative scoring systems for all parameters. Because an in depth analysis of the ALS mouse model usually requires an immunohistochemical examination of the spinal cord, we demonstrate its preparation in detail applying the dorsal laminectomy method. Exemplary histological findings are demonstrated. The comprehensive application of the depicted examination methods in studies on the mouse model of ALS will enable the researcher to reliably test future therapeutic options which can provide a basis for later human clinical trials.

Clinical Testing and Spinal Cord Removal in a Mouse Model for Amyotrophic Lateral Sclerosis ALS

A mouse model for amyotrophic lateral sclerosis (ALS) is examined clinically and behaviorally. As a prerequisite for an accompanying immunohistological analysis the preparation of the spinal cord is depicted in detail.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder resulting in progressive degeneration of motoneurons. Peak of onset is around 60 ...

A Contusion Model of Severe Spinal Cord Injury in Rats

The translational potential of novel treatments should be investigated in severe spinal cord injury (SCI) contusion models. A detailed methodology is described to obtain a consistent model of severe SCI. Use of a stereotactic frame and computer controlled impactor allows for creation of reproducible injury. Hypothermia and urinary tract infection pose significant challenges in the post-operative period. Careful monitoring of animals with daily weight recording and bladder expression allows for early detection of post-operative complications. The functional results of this contusion model are equivalent to transection models. The contusion model can be utilized to evaluate the efficacy of both neuroprotective and neuroregenerative approaches.

A contusion model of severe spinal cord injury is described. Detailed pre-operative, operative and post-operative steps are described to obtain a consistent model.

The translational potential of novel treatments should be investigated in severe spinal cord injury (SCI) contusion models. A detailed methodology is ...

Combined In vivo Optical and &#181;CT Imaging to Monitor Infection, Inflammation, and Bone Anatomy in an Orthopaedic Implant Infection in Mice

Multimodality imaging has emerged as a common technological approach used in both preclinical and clinical research. Advanced techniques that combine in vivo optical and &#956;CT imaging allow the visualization of biological phenomena in an anatomical context. These imaging modalities may be especially useful to study conditions that impact bone. In particular, orthopaedic implant infections are an important problem in clinical orthopaedic surgery. These infections are difficult to treat because bacterial biofilms form on the foreign surgically implanted materials, leading to persistent inflammation, osteomyelitis and eventual osteolysis of the bone surrounding the implant, which ultimately results in implant loosening and failure. Here, a mouse model of an infected orthopaedic prosthetic implant was used that involved the surgical placement of a Kirschner-wire implant into an intramedullary canal in the femur in such a way that the end of the implant extended into the knee joint. In this model, LysEGFP mice, a mouse strain that has EGFP-fluorescent neutrophils, were employed in conjunction with a bioluminescent Staphylococcus aureus strain, which naturally emits light. The bacteria were inoculated into the knee joints of the mice prior to closing the surgical site. In vivo bioluminescent and fluorescent imaging was used to quantify the bacterial burden and neutrophil inflammatory response, respectively. In addition, &#956;CT imaging was performed on the same mice so that the 3D location of the bioluminescent and fluorescent optical signals could be co-registered with the anatomical &#956;CT images. To quantify the changes in the bone over time, the outer bone volume of the distal femurs were measured at specific time points using a semi-automated contour based segmentation process. Taken together, the combination of in vivo bioluminescent/fluorescent imaging with &#956;CT imaging may be especially useful for the noninvasive monitoring of the infection, inflammatory response and anatomical changes in bone over time.

Combined In vivo Optical and  &amp;#181;CT Imaging to Monitor Infection, Inflammation, and Bone Anatomy in an Orthopaedic Implant Infection in Mice

Combined optical and &#956;CT imaging in a mouse model of orthopaedic implant infection, utilizing a bioluminescent engineered strain of Staphylococcus aureus, provided the capability to noninvasively and longitudinally monitor the dynamics of the bacterial infection, as well as the corresponding inflammatory response and anatomical changes in the bone.

Multimodality imaging has emerged as a common technological approach used in both preclinical and clinical research. Advanced techniques that combine in ...

Controlled Cortical Impact Model for Traumatic Brain Injury

Every year over a million Americans suffer a traumatic brain injury (TBI). Combined with the incidence of TBIs worldwide, the physical, emotional, social, and economical effects are staggering. Therefore, further research into the effects of TBI and effective treatments is necessary. The controlled cortical impact (CCI) model induces traumatic brain injuries ranging from mild to severe. This method uses a rigid impactor to deliver mechanical energy to an intact dura exposed following a craniectomy. Impact is made under precise parameters at a set velocity to achieve a pre-determined deformation depth. Although other TBI models, such as weight drop and fluid percussion, exist, CCI is more accurate, easier to control, and most importantly, produces traumatic brain injuries similar to those seen in humans. However, no TBI model is currently able to reproduce pathological changes identical to those seen in human patients. The CCI model allows investigation into the short-term and long-term effects of TBI, such as neuronal death, memory deficits, and cerebral edema, as well as potential therapeutic treatments for TBI.

Traumatic brain injuries (TBIs) remain a serious health problem. Using the controlled cortical impact surgery model, research on the effects of TBI and possible treatment methods may be performed.

Every year over a million Americans suffer a traumatic brain injury (TBI).  Combined with the incidence of TBIs worldwide, the physical, emotional, ...

Intrauterine Telemetry to Measure Mouse Contractile Pressure In Vivo

A complex integration of molecular and electrical signals is needed to transform a quiescent uterus into a contractile organ at the end of pregnancy. Despite the discovery of key regulators of uterine contractility, this process is still not fully understood. Transgenic mice provide an ideal model in which to study parturition. Previously, the only method to study uterine contractility in the mouse was ex vivo isometric tension recordings, which are suboptimal for several reasons. The uterus must be removed from its physiological environment, a limited time course of investigation is possible, and the mice must be sacrificed. The recent development of radiometric telemetry has allowed for longitudinal, real-time measurements of in vivo intrauterine pressure in mice. Here, the implantation of an intrauterine telemeter to measure pressure changes in the mouse uterus from mid-pregnancy until delivery is described. By comparing differences in pressures between wild type and transgenic mice, the physiological impact of a gene of interest can be elucidated. This technique should expedite the development of therapeutics used to treat myometrial disorders during pregnancy, including preterm labor.

Intrauterine Telemetry to Measure Mouse Contractile Pressure In Vivo

This manuscript provides a protocol for implanting telemeters in the mouse for the purpose of measuring intrauterine pressures during pregnancy.

A complex integration of molecular and electrical signals is needed to transform a quiescent uterus into a contractile organ at the end of pregnancy. ...

A Neonatal Mouse Spinal Cord Compression Injury Model

Spinal cord injury (SCI) typically causes devastating neurological deficits, particularly through damage to fibers descending from the brain to the spinal cord. A major current area of research is focused on the mechanisms of adaptive plasticity that underlie spontaneous or induced functional recovery following SCI. Spontaneous functional recovery is reported to be greater early in life, raising interesting questions about how adaptive plasticity changes as the spinal cord develops. To facilitate investigation of this dynamic, we have developed a SCI model in the neonatal mouse. The model has relevance for pediatric SCI, which is too little studied. Because neural plasticity in the adult involves some of the same mechanisms as neural plasticity in early life1, this model may potentially have some relevance also for adult SCI. Here we describe the entire procedure for generating a reproducible spinal cord compression (SCC) injury in the neonatal mouse as early as postnatal (P) day 1. SCC is achieved by performing a laminectomy at a given spinal level (here described at thoracic levels 9-11) and then using a modified Yasargil aneurysm mini-clip to rapidly compress and decompress the spinal cord. As previously described, the injured neonatal mice can be tested for behavioral deficits or sacrificed for ex vivo physiological analysis of synaptic connectivity using electrophysiological and high-throughput optical recording techniques1. Earlier and ongoing studies using behavioral and physiological assessment have demonstrated a dramatic, acute impairment of hindlimb motility followed by a complete functional recovery within 2 weeks, and the first evidence of changes in functional circuitry at the level of identified descending synaptic connections1.

This article describes a method for generating a reproducible spinal cord compression injury (SCI) in the neonatal mouse. The model provides an advantageous platform for studying mechanisms of adaptive plasticity that underlie spontaneous functional recovery.

Spinal cord injury (SCI) typically causes devastating neurological deficits, particularly through damage to fibers descending from the brain to the spinal ...

Stem-cell Based Engineered Immunity Against HIV Infection in the Humanized Mouse Model

With the rapid development of stem cell-based gene therapies against HIV, there is pressing requirement for an animal model to study the hematopoietic differentiation and immune function of the genetically modified cells. The humanized Bone-marrow/Liver/Thymus (BLT) mouse model allows for full reconstitution of a human immune system in the periphery, which includes T cells, B cells, NK cells and monocytes. The human thymic implant also allows for thymic selection of T cells in autologous thymic tissue. In addition to the study of HIV infection, the model stands as a powerful tool to study differentiation, development and functionality of cells derived from hematopoietic stem cells (HSCs). Here we outline the construction of humanized non-obese diabetic (NOD)-severe combined immunodeficient (SCID)-common gamma chain knockout (c&#947;-/-)-Bone-marrow/Liver/Thymus (NSG-BLT) mice with HSCs transduced with CD4 chimeric antigen receptor (CD4CAR) lentivirus vector. We show that the CD4CAR HSCs can successfully differentiate into multiple lineages and have anti-HIV activity. The goal of the study is to demonstrate the use of NSG-BLT mouse model as an in vivo model for engineered immunity against HIV. It is worth noting that, because lentivirus and human tissue is used, experiments and surgeries should be performed in a Class II biosafety cabinet in a Biosafety Level 2 (BSL2) with special precautions (BSL2+) facility.

This protocol describes the methods in constructing a humanized bone-marrow/liver/thymus mouse model with stem cell-based engineered immunity against HIV infection.

With the rapid development of stem cell-based gene therapies against HIV, there is pressing requirement for an animal model to study the hematopoietic ...

Depletion of Mouse Cells from Human Tumor Xenografts Significantly Improves Downstream Analysis of Target Cells

The use of in vitro cell line models for cancer research has been a useful tool. However, it has been shown that these models fail to reliably mimic patient tumors in different assays1. Human tumor xenografts represent the gold standard with respect to tumor biology, drug discovery, and metastasis research 2-4. Tumor xenografts can be derived from different types of material like tumor cell lines, tumor tissue from primary patient tumors4 or serially transplanted tumors. When propagated in vivo, xenografted tissue is infiltrated and vascularized by cells of mouse origin. Multiple factors such as the tumor entity, the origin of xenografted material, growth rate and region of transplantation influence the composition and the amount of mouse cells present in tumor xenografts. However, even when these factors are kept constant, the degree of mouse cell contamination is highly variable.
Contaminating mouse cells significantly impair downstream analyses of human tumor xenografts. As mouse fibroblasts show high plating efficacies and proliferation rates, they tend to overgrow cultures of human tumor cells, especially slowly proliferating subpopulations. Mouse cell derived DNA, mRNA, and protein components can bias downstream gene expression analysis, next-generation sequencing, as well as proteome analysis 5. To overcome these limitations, we have developed a fast and easy method to isolate untouched human tumor cells from xenografted tumor tissue. This procedure is based on the comprehensive depletion of cells of mouse origin by combining automated tissue dissociation with the benchtop tissue dissociator and magnetic cell sorting. Here, we demonstrate that human target cells can be can be obtained with purities higher than 96% within less than 20 min independent of the tumor type.

Human tumor xenografts are vascularized and infiltrated by cells of mouse origin during the growth phase in vivo. To circumvent the bias caused by these contaminating cells during downstream analysis, we developed a method allowing for comprehensive depletion of all mouse cells by magnetic cell sorting.

The use of in vitro cell line models for cancer research has been a useful tool. However, it has been shown that these models fail to reliably mimic ...