El trabajo fue apoyado en parte por el Servicio de Salud Pública 1R01AI081568 subvención del NIAID para YW y por las generosas donaciones de los donantes y los jinetes de la Cabalgata 2009 NYCDC SIDA organizada por M. Rosen y Day2 Inc.

1. La transfección de plásmidos para la producción de las partículas lentivirales Ap-dependiente Set up: The Rev-dependiente GFP vector lentiviral, PNL-GFP-RRE-SA, se ha descrito anteriormente 4,5,6. Para montar en una partícula viral, el plásmido se contransfected en HEK293 células T con un VIH-1 en la construcción de envases, pCMVΔ8.2 (amablemente proporcionados por el Dr. Dider Trono), y un plásmido que lleva la glicoproteína VSV-G (pHCMV-G) . La transfección se realizó mediante el método de fosfato de calcio. Preparación de tampones: 10 X HBS (Hepes salina tamponada) se preparó disolviendo 5 g de Hepes, 8 g de NaCl, 0,37 g de KCl, 1 g de dextrosa, 0,103 g de Na 2 HPO 4 (anhidro) en 100 ml de H 2 O. Alícuota the10 X EPF buffer en alícuotas de 1 ml y almacenar a -20 ° C. En el momento de la transfección, convertir el 10 X 2 X HBS para HBS con H 2 O (1: 5 de dilución), y ajustar el pH entre 7,05 a 7,12. (De 10 ml de HBS 2 X, por lo general requiere de aproximadamente 50 l de NaOH 1M). Filtro de esterilizar el 2X tampón HBS, al pasar por un filtro Millipore de 0,22 M. CaCI buffer 2 se realizó mediante la disolución de CaCl 2 en 10 mM Hepes a una concentración final de 2 millones. Ajustar el pH a 5.8, filtro de esterilización de la memoria intermedia y se almacenan a 4 ° C. Procedimiento: <ol><li> Un día antes de la transfección, las semillas de 2 x 10 6 células HEK293T en una de 100 mm de Petri plato, y hacer crecer las células durante la noche en 10 ml de DMEM + 10% de SFB a 37 ° C, 5% de CO 2. </li><li> Al día siguiente, retirar el sobrenadante de las células y reemplazar con 5 ml de DMEM + 10% de SFB, continuamente células en cultivo durante 4 horas. </li><li> En un tubo de poliestireno de 5 ml, añadir 480 l 2X tampón HBS. </li><li> En un segundo tubo de poliestireno de 5 ml, añadir 60 l 2 M de CaCl2 buffer, el ADN del plásmido y transfección buffer TE (1 mM Tris, 25 mM EDTA, pH 8,0) hasta un volumen total de 480 mL. Para cada plato de Petri, los plásmidos se debe agregar en la proporción de 10 mg de PNL-GFP-RRE-SA, 7,5 g de pCMVΔR8.3, y 2,5 mg de pHCMV-G. </li><li> Añadir el plásmido ADN-CaCl2 mezcla gota a gota en el tubo de 2 X HBS, e incubar a temperatura ambiente durante 30 minutos. Un fino precipitado se forma. </li><li> Agregue el l 960 de la mezcla gota a gota con una pipeta a las células. Se incuba a 37 ° C CO, 5% 2 durante la noche. </li><li> Al día siguiente, separar el sobrenadante y agregar 10 ml DMEM + 10% de SFB, y continuamente se incuban las células a 37 ° C CO, 5% de CO2 durante la noche. </li><li> A las 48 horas después de la transfección, la cosecha del virus mediante la eliminación del sobrenadante y transferirlo en tubos de 50 ml estériles. Añadir nuevo 10 ml fresca FBS DMEM + 10% en cada plato de Petri y siguen a la cultura durante la noche. Guardar el sobrenadante del virus a 4 ° C. </li><li> Continuar la cosecha de 72 horas después de la transfección mediante la recolección del sobrenadante. Combine todos los sobrenadantes y centrifugar el sobrenadante a 500 xg durante 15 minutos para sedimentar y eliminar los desechos celulares. </li><li> El sobrenadante se recogieron y se filtra a través de un filtro Millipore de 0,22 M. El virus se concentró aún más a través de columnas de exclusión de tamaño. </li></ol> 2. Concentrar las partículas virales y determinar título viral <ol><li> Las partículas virales se concentraron por una columna de exclusión por tamaño (100.000 MW cortado, Centricoin). Sobrenadante viral se ha cargado en la columna, y se centrifuga a 6000 xg a 4 ° C durante 15 minutos. </li><li> Sobrenadante viral concentrada se recogió, alícuotas, y almacenadas a -80 ° C. </li><li> El título viral se determinó por la infección de un TNF-tratamiento, el VIH-1 positivos línea celular chaqueta, J1.1 7. Las células fueron cultivadas en una placa de 96 pocillos de 2,5 x 10 5 células por ml (100 ml de volumen total), e infectados con 100 ml de diluciones seriadas VNL-GFP-RRE-SA por una semana. El título (TCID50) de la partícula se calculó contando los pozos GFP positivos siguiendo el método de Reed y Muench 8. </li></ol> 3. Marcando el VIH-1 células positivas con la partícula lentivirales, VNL-GFP-RRE-SA Montaje: una T CD4 líneas de células humanas, CEM-SS, estaba infectado primero con el VIH-1. A las 48 horas post-infección, las células fueron superinfección con las partículas lentiviral, VNL-GFP-RRE-SA. Después de la sobreinfección por otros dos días, las buenas prácticas agrarias de células positivas fueron analizadas por citometría de flujo. Como control, el VIH-1 no infectadas CEM-SS células fueron infectadas con idéntica VNL-GFP-RRE-SA. Sólo la pandemia del VIH-1-infected CEM-SS células dieron lugar a las células GFP positivos, pero no el VIH-1 no infectadas CEM-SS células. Procedimiento: <ol><li> Dos horas antes de la infección, añadir polybrane a una concentración final de 4 mg / mL. Recuento de células y tomar 2 x 10 5 células por cada infección. Infectar a las células con 200 ng (p24) del VIH-1 NL4-3 durante 2 horas. </li><li> Lavado de las células por centrifugación a 300 xg durante 10 minutos, resuspendercélulas en 2 x 10 5 células / ml, y la cultura a 37 ° C durante 48 horas. </li><li> Recuento de células y tomar 2 x 10 5 células por la infección por VNL-GFP-RRE-SA. Añadir 100 ml de VNL-GFP-RRE-SA y se incuba a 37 ° C durante la noche. Lavar las células y resuspender en 2 x 10 5 células / ml. </li><li> Realizar un análisis de citometría de flujo a las 48 horas después de la superinfección. Las células infectadas se sedimentaron y se resuspendieron en 500 ml paraformaldehede 1%, incubados a temperatura ambiente durante 20 minutos, y luego se analizaron en un analizador FACScan (Becton Dickenson). </li></ol> 4. Resultados representante Si los experimentos se realizó con éxito, una población considerable GFP se detectó en el VIH-1-infected CEM-SS células por el citómetro de flujo, mientras que, en el control, las células GFP positivos no se detecta el VIH-1 no infectadas CEM-SS las células. Si los experimentos se realizó con éxito, el vector lentiviral Ap-dependiente, VNL-GFP-RRE-SA, permitirá una detección muy específica de la replicación del VIH en las poblaciones de células que viven, a través de la medición de la proteína verde fluorescente (GFP) de expresión. En este ejemplo, se recogieron CEM-SS células fueron teñidas con un anticuerpo marcado con PE rata monoclonal contra CD24 de ratón, HSA, y luego se analizaron en un citómetro de flujo, tanto para la HSA y la expresión de GFP. <img src="/files/ftp_upload/2198/2198fig1.jpg" alt="Figura 1" /> Figura 1. Como se muestra aquí, una población considerable GFP se detectó en el VIH-1 las células infectadas por superinfección con VNL-GFP-RRE-SA (Figura 1c). En contraste, las células GFP positivos no se han detectado, ya sea en el VIH-1 no infectadas CEM-SS células sin sobreinfección lentiviral (Figura 1a) o el VIH-1 las células no infectadas con sobreinfección lentiviral (Figura 1b).

<ol>
	<li>Garcia, J. A., Wu, F. K., Mitsuyasu, R., Gaynor, R. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Interactions+of+cellular+proteins+involved+in+the+transcriptional+regulation+of+the+human+immunodeficiency+virus.">Interactions of cellular proteins involved in the transcriptional regulation of the human immunodeficiency virus.</a> EMBO Journal. 6, 3761-3770 (1987).</li><li>Merzouki, A. <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+gp120/160+expressing+cells+upregulate+HIV-1+LTR+directed+gene+expression+in+a+cell+line+transfected+with+HIV-1+LTR-reporter+gene+constructs.">HIV-1 gp120/160 expressing cells upregulate HIV-1 LTR directed gene expression in a cell line transfected with HIV-1 LTR-reporter gene constructs.</a> Cell Mol Biol (Noisy-le-grand. 41, 445-452 (1995).</li><li>Aguilar-Cordova, E., Chinen, J., Donehower, L., Lewis, D. E., Belmont, J. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+sensitive+reporter+cell+line+for+HIV-1+tat+activity,+HIV-1+inhibitors,+and+T+cell+activation+effects.">A sensitive reporter cell line for HIV-1 tat activity, HIV-1 inhibitors, and T cell activation effects.</a> AIDS Res Hum Retroviruses. 10, 295-301 (1994).</li><li>Wu, Y., Beddall, M. H., Marsh, J. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rev-dependent+lentiviral+expression+vector.">Rev-dependent lentiviral expression vector.</a> Retrovirology. 4, 12-12 (2007).</li><li>Wu, Y., Beddall, M. H., Marsh, J. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rev-dependent+indicator+T+cell+line.">Rev-dependent indicator T cell line.</a> Current HIV Research. 5, 395-403 (2007).</li><li>Young, J., Tang, Z., Yu, Q., Yu, D., Wu, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Selective+killing+of+HIV-1-positive+macrophages+and+T+Cells+by+the+Rev-dependent+lentivirus+carrying+anthrolysin+O+from+Bacillus+anthracis.">Selective killing of HIV-1-positive macrophages and T Cells by the Rev-dependent lentivirus carrying anthrolysin O from Bacillus anthracis.</a> Retrovirology. 5, 36-36 (2008).</li><li>Perez, V. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+HIV-1-infected+T+cell+clone+defective+in+IL-2+production+and+Ca2++mobilization+after+CD3+stimulation.">An HIV-1-infected T cell clone defective in IL-2 production and Ca2+ mobilization after CD3 stimulation.</a> Journal of Immunology. 147, 3145-3148 (1991).</li><li>Reed, L. J., Muench, H. <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+method+of+estimating+fifty+percent+endpoints.">A simple method of estimating fifty percent endpoints.</a> American Journal of Hygiene. 27, 493-497 (1938).</li></ol>

Al igual que con los vectores de expresión antes desarrollado Tat-dependientes, el sistema de Apocalipsis se describe aquí es una explotación de un proceso de evolución del VIH. La inclusión de Rev-dependencia hace que el vector de expresión basado en LTR depende en gran medida la presencia de la replicación del VIH. La aplicación de este vector como se informó aquí, un reportero de virus VIH-dependiente, ofrece un nuevo enfoque nuevo para identificar el VIH de células positivas. El vector permite el examen de las células vivas, se puede expresar cualquier gen para la experimentación básica y clínica, y como un lentivirus pseudo-tipo tiene acceso a más tipos de células y tejidos.

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		<div>
		<table border="1">
		<thead>
		<tr>
		<th>Material Name</th>
		<th>Type</th>
		<th>Company</th>
		<th>Catalogue Number</th>
		<th>Comment</th>
		</tr>
		</thead>
		<tbody>
		
<tr>
<td>Biosafety Cabinet</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>37&deg;C 5%CO2 incubator</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Flow cytometer</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>FACSCalibur</td>
<td>&nbsp;</td>
<tr>
<td>Centrifuge</td>
<td>&nbsp;</td>
<td>Beckman</td>
<td>Allega&trade;6KR</td>
<td>&nbsp;</td>
<tr>
<td>4&deg;C regrigerator</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>-20&deg;C refrigerator</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td> -80&deg;C refrigerator</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Cell counter</td>
<td>&nbsp;</td>
<td>Nexcelom</td>
<td>Cellometer&trade; AutoT4</td>
<td>&nbsp;</td>
<tr>
<td>HEK293T cell line</td>
<td>&nbsp;</td>
<td>NIH</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>CEM-SS cell line</td>
<td>&nbsp;</td>
<td>NIH</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>Jurkat cell line J1.1</td>
<td>&nbsp;</td>
<td>NIH</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>DMEM</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>11965-118</td>
<td>&nbsp;</td>
<tr>
<td>RPMI 1640</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>21870</td>
<td>&nbsp;</td>
<tr>
<td>HI FBS</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>10438-018</td>
<td>&nbsp;</td>
<tr>
<td>HIV-1NL4-3</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>prepared by tranfsection of HeLa cells with cloned proviral DNA</td>
</tr>
<tr>
<td>pNL-GFP-RRE</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>copmlete deletion of all HIV ORFs of pNL4-3</td>
</tr>
<tr>
<td>pNL-GFP-RRE-SA</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>Insert HIV-1 A5 and D4 into pNL-GFP-RRE</td>
</tr>
<tr>
<td>pCMV&Delta;8.2</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>provided by Dr. Dider Trono</td>
</tr>
<tr>
<td>pHCMV-G</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>10 x HBS (Hepes Buffered Saline)</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>11344-041</td>
<td>&nbsp;</td>
<tr>
<td>2M CaCl2 buffer</td>
<td>&nbsp;</td>
<td>Invitrogen</td>
<td>S-013-154-10</td>
<td>&nbsp;</td>
<tr>
<td>1% paraformaldehy</td>
<td>&nbsp;</td>
<td>Sigma Aldrich</td>
<td>158127</td>
<td>&nbsp;</td>
<tr>
<td>Bleach</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>50ml Falcon tubes</td>
<td>&nbsp;</td>
<td>BD Bioscience</td>
<td>358206</td>
<td>&nbsp;</td>
<tr>
<td>5ml round bottom tubes</td>
<td>&nbsp;</td>
<td>BD Bioscience</td>
<td>352063</td>
<td>&nbsp;</td>
<tr>
<td>0.45&mu;M Millipore filter</td>
<td>&nbsp;</td>
<td>Millipore</td>
<td>SLHA033SS</td>
<td>&nbsp;</td>
<tr>
<td>0.20&mu;M Millipore filter</td>
<td>&nbsp;</td>
<td>Millipore</td>
<td>SLFG85000</td>
<td>&nbsp;</td>
<tr>
<td>100mm Petri-dish</td>
<td>&nbsp;</td>
<td>Sigma Aldrich</td>
<td>CLS430588</td>
<td>&nbsp;</td>
<tr>
<td>Size-exclusion column (100,000MW cut off)</td>
<td>&nbsp;</td>
<td>SartoriuStedim biotech</td>
<td>VS2041</td>
<td>&nbsp;</td>
<tr>
<td>2ml frozen tube</td>
<td>&nbsp;</td>
<td>Axygen</td>
<td>SCT-200</td>
<td>&nbsp;</td>
<tr>
<td>96-well plate</td>
<td>&nbsp;</td>
<td>BD Bioscience</td>
<td>353227</td>
<td>&nbsp;</td>
<tr>
<td>1.7mL Microcentrifuge Tube</td>
<td>&nbsp;</td>
<td>Axygen</td>
<td>MCT- 175-C</td>
<td>&nbsp;</td>		</tbody>
		</table>
		</div>

specific marking of hiv-1 positive cells using a rev-dependent lentiviral vector expressing the green fluorescent protein

La mayoría de los vectores de la expresión del VIH-respuesta se basan en el promotor del VIH, la repetición terminal larga (LTR). Mientras que responda a una de las primeras proteínas del VIH, Tat, el LTR es también sensible a los estados de activación celular y la actividad de la cromatina local, donde la integración se ha producido. Esto puede resultar en altas tasas de VIH-independiente de la actividad, y ha limitado la utilidad de la LTR basado en reportero para marcar las células con VIH 1,2,3. Aquí se construyó un vector de expresión lentiviral que posee, además de la LTR-Tat respuesta, numerosas secuencias de ADN del VIH que incluyen el elemento Ap-respuesta y los sitios de empalme VIH 4,5,6. El vector se incorporó a un reportero lentiviral virus, lo que permite una detección muy específica de la replicación del VIH en las poblaciones de células vivas. La actividad del vector se mide por la expresión de la proteína de fluorescencia verde (GFP). La aplicación de este vector como se informó aquí ofrece un enfoque alternativo nuevo a los métodos existentes, como la PCR in situ o tinción del antígeno, para identificar el VIH de células positivas. El vector también puede expresar genes terapéuticos para la experimentación básica o clínica para orientar el VIH de células positivas.

Watch this Scientific Journal Video about Specific Marking of HIV-1 Positive Cells using a Rev-dependent Lentiviral Vector Expressing the Green Fluorescent Protein at JoVE.com

Specific Marking of HIV-1 Positive Cells using a Rev-dependent Lentiviral Vector Expressing the Green Fluorescent Protein

Hemos desarrollado un vector lentiviral que posee, además de la LTR-Tat respuesta, el elemento de respuesta Rev (RRE) que pueden regular la expresión del gen de una forma del VIH-1 Tat y Rev-dependiente. El vector permite la detección específica de la replicación del VIH en las células vivas a través de la expresión de GFP.

Marcado específico del VIH-1 células positivas utilizando un vector lentiviral Ap-dependientes que expresan la proteína verde fluorescente

Most of HIV-responsive expression vectors are based on the HIV promoter, the long terminal repeat (LTR). While responsive to an early HIV protein, Tat, ...

specific-marking-hiv-1-positive-cells-using-rev-dependent-lentiviral

Research

JoVE Journal

Immunology and Infection

12.8K vistas.  George Mason University. Hemos desarrollado un vector lentiviral que posee, además de la LTR-Tat respuesta, el elemento de respuesta Rev (RRE) que pueden regular la expresión del gen de una forma del VIH-1 Tat y Rev-dependiente. El vector permite la detección específica de la replicación del VIH en las células vivas a través de la expresión de GFP.

Video: Specific Marking of HIV-1 Positive Cells using a Rev-dependent Lentiviral Vector Expressing the Green Fluorescent Protein

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.

Inferencia genotípica del VIH-1 tropismo utilizando la población basada en la secuencia de 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 ...

Investigación

Inmunología e Infección

Prediction of HIV-1 Coreceptor Usage (Tropism) by Sequence Analysis using a Genotypic Approach

Maraviroc (MVC) is the first licensed antiretroviral drug from the class of coreceptor antagonists. It binds to the host coreceptor CCR5, which is used by the majority of HIV strains in order to infect the human immune cells (Fig. 1). Other HIV isolates use a different coreceptor, the CXCR4. Which receptor is used, is determined in the virus by the Env protein (Fig. 2). Depending on the coreceptor used, the viruses are classified as R5 or X4, respectively. MVC binds to the CCR5 receptor inhibiting the entry of R5 viruses into the target cell. During the course of disease, X4 viruses may emerge and outgrow the R5 viruses. Determination of coreceptor usage (also called tropism) is therefore mandatory prior to administration of MVC, as demanded by EMA and FDA. 
The studies for MVC efficiency MOTIVATE, MERIT and 1029 have been performed with the Trofile assay from Monogram, San Francisco, U.S.A. This is a high quality assay based on sophisticated recombinant tests. The acceptance for this test for daily routine is rather low outside of the U.S.A., since the European physicians rather tend to work with decentralized expert laboratories, which also provide concomitant resistance testing. These laboratories have undergone several quality assurance evaluations, the last one being presented in 20111.
For several years now, we have performed tropism determinations based on sequence analysis from the HIV env-V3 gene region (V3)2. This region carries enough information to perform a reliable prediction. 
The genotypic determination of coreceptor usage presents advantages such as: shorter turnover time (equivalent to resistance testing), lower costs, possibility to adapt the results to the patients' needs and possibility of analysing clinical samples with very low or even undetectable viral load (VL), particularly since the number of samples analysed with VL&lt;1000 copies/&mu;l roughly increased in the last years (Fig. 3).
The main steps for tropism testing (Fig. 4) demonstrated in this video: 
1. Collection of a blood sample 
 2. Isolation of the HIV RNA from the plasma and/or HIV proviral DNA from blood mononuclear cells 
 3. Amplification of the env region 
 4. Amplification of the V3 region 
 5. Sequence reaction of the V3 amplicon 
 6. Purification of the sequencing samples 
 7. Sequencing the purified samples 
 8. Sequence editing 
 9. Sequencing data interpretation and tropism prediction

Prediction of HIV-1 Coreceptor Usage Tropism by Sequence Analysis using a Genotypic Approach

The prediction of the coreceptor usage of HIV-1 is required for the administration of a new class of antiretroviral drugs, i.e. coreceptor antagonists. It can be performed by sequence analysis of the env gene and subsequent interpretation through an internet based interpretation system (geno2pheno[coreceptor]).

Predicción del VIH-1 usos correceptor (tropismo) por análisis de secuencia utilizando un enfoque genotípica

Maraviroc (MVC) is the first licensed antiretroviral drug from the class of coreceptor antagonists. It binds to the host coreceptor CCR5, which is used by ...

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.

En uncoating in vitro del VIH-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 ...

Assessing the Innate Sensing of HIV-1 Infected CD4+ T Cells by Plasmacytoid Dendritic Cells Using an Ex vivo Co-culture System.

HIV-1 innate sensing requires direct contact of infected CD4+ T cells with plasmacytoid dendritic cells (pDCs). In order to study this process, the protocols described here use freshly isolated human peripheral blood mononuclear cells (PBMCs) or plasmacytoid dendritic cells (pDCs) to sense infections in either T cell line (MT4) or heterologous primary CD4+ T cells. In order to ensure proper sensing, it is essential that PBMC are isolated immediately after blood collection and that optimal percentage of infected T cells are used. Furthermore, multi-parametric flow cytometric staining can be used to confirm that PBMC samples contain the different cell lineages at physiological ratios. A number of controls can also be included to evaluate viability and functionality of pDCs. These include, the presence of specific surface markers, assessing cellular responses to known agonist of Toll-Like Receptors (TLR) pathways, and confirming a lack of spontaneous type-I interferon (IFN) production. In this system, freshly isolated PBMCs or pDCs are co-cultured with HIV-1 infected cells in 96 well plates for 18-22 hr. Supernatants from these co-cultures are then used to determine the levels of bioactive type-I IFNs by monitoring the activation of the ISGF3 pathway in HEK-Blue IFN-&#945;/&#946; cells. Prior and during co-culture conditions, target cells can be subjected to flow cytometric analysis to determine a number of parameters, including the percentage of infected cells, levels of specific surface markers, and differential killing of infected cells. Although, these protocols were initially developed to follow type-I IFN production, they could potentially be used to study other imuno-modulatory molecules released from pDCs and to gain further insight into the molecular mechanisms governing HIV-1 innate sensing.

Assessing the Innate Sensing of HIV-1 Infected CD4+ T Cells by Plasmacytoid Dendritic Cells Using an Ex vivo Co-culture System.

Unlike cell-free HIV-1 particles, infected CD4+ T cells are effectively sensed by plasmacytoid dendritic cells (pDCs). This manuscript describes a method where peripheral blood mononuclear cells (PBMCs) or isolated pDCs are co-cultured with HIV-1 infected T cells to evaluate innate sensing by pDCs as assessed by release of type-I IFN.

La evaluación de la innata de detección de VIH-1 CD4 infectados<sup&gt; +</sup&gt; Células T por las células dendríticas plasmocitoides Usando un<em&gt; Ex vivo</em&gt; Co-cultura del sistema.

HIV-1 innate sensing requires direct contact of infected CD4+ T cells with plasmacytoid dendritic cells (pDCs). In order to study this process, the ...

Conformational Evaluation of HIV-1 Trimeric Envelope Glycoproteins Using a Cell-based ELISA Assay

HIV-1 envelope glycoproteins (Env) mediate viral entry into target cells and are essential to the infectious cycle. Understanding how those glycoproteins are able to fuel the fusion process through their conformational changes could lead to the design of better, more effective immunogens for vaccine strategies. Here we describe a cell-based ELISA assay that allows studying the recognition of trimeric HIV-1 Env by monoclonal antibodies. Following expression of HIV-1 trimeric Env at the surface of transfected cells, conformation specific anti-Env antibodies are incubated with the cells. A horseradish peroxidase-conjugated secondary antibody and a simple chemiluminescence reaction are then used to detect bound antibodies. This system is highly flexible and can detect Env conformational changes induced by soluble CD4 or cellular proteins. It requires minimal amount of material and no highly-specialized equipment or know-how. Thus, this technique can be established for medium to high throughput screening of antigens and antibodies, such as newly-isolated antibodies.

Understanding viral surface antigens conformations is required to evaluate antibody neutralization and guide the design of effective vaccine immunogens. Here we describe a cell-based ELISA assay that allows the study of the recognition of trimeric HIV-1 Env expressed at the surface of transfected cells by specific anti-Env antibodies.

Evaluación conformacional del VIH-1 glicoproteínas de la envoltura trimérica El uso de un ELISA ensayo basado en células

HIV-1 envelope glycoproteins (Env) mediate viral entry into target cells and are essential to the infectious cycle. Understanding how those glycoproteins ...

Isolation of Exosomes from the Plasma of HIV-1 Positive Individuals

Exosomes are small vesicles ranging in size from 30 nm to 100 nm that are released both constitutively and upon stimulation from a variety of cell types. They are found in a number of biological fluids and are known to carry a variety of proteins, lipids, and nucleic acid molecules. Originally thought to be little more than reservoirs for cellular debris, the roles of exosomes regulating biological processes and in diseases are increasingly appreciated.
Several methods have been described for isolating exosomes from cellular culture media and biological fluids. Due to their small size and low density, differential ultracentrifugation and/or ultrafiltration are the most commonly used techniques for exosome isolation. However, plasma of HIV-1 infected individuals contains both exosomes and HIV viral particles, which are similar in size and density. Thus, efficient separation of exosomes from HIV viral particles in human plasma has been a challenge.
To address this limitation, we developed a procedure modified from Cantin et. al., 2008 for purification of exosomes from HIV particles in human plasma. Iodixanol velocity gradients were used to separate exosomes from HIV-1 particles in the plasma of HIV-1 positive individuals. Virus particles were identified by p24 ELISA. Exosomes were identified on the basis of exosome markers acetylcholinesterase (AChE), and the CD9, CD63, and CD45 antigens. Our gradient procedure yielded exosome preparations free of virus particles. The efficient purification of exosomes from human plasma enabled us to examine the content of plasma-derived exosomes and to investigate their immune modulatory potential and other biological functions.

Techniques describing a gradient procedure to separate exosomes from human immunodeficiency virus (HIV) particles are described. This procedure was used to isolate exosomes away from HIV particles in human plasma from HIV-infected individuals. The isolated exosomes were analyzed for cytokine/chemokine content.

Aislamiento de exosomas del plasma de VIH-1 en individuos positivos

Exosomes are small vesicles ranging in size from 30 nm to 100 nm that are released both constitutively and upon stimulation from a variety of cell types. ...

SILAC Based Proteomic Characterization of Exosomes from HIV-1 Infected Cells

Proteomics is the large-scale analysis of proteins. Proteomic techniques, such as liquid chromatography tandem mass spectroscopy (LC-MS/MS), can characterize thousands of proteins at a time. These powerful techniques allow us to have a systemic understanding of cellular changes, especially when cells are subjected to various stimuli, such as infections, stresses, and specific test conditions. Even with recent developments, analyzing the exosomal proteome is time-consuming and often involves complex methodologies. In addition, the resultant large dataset often needs robust and streamlined analysis in order for researchers to perform further downstream studies. Here, we describe a SILAC-based protocol for characterizing the exosomal proteome when cells are infected with HIV-1. The method is based on simple isotope labeling, isolation of exosomes from differentially labeled cells, and mass spectrometry analysis. This is followed by detailed data mining and bioinformatics analysis of the proteomic hits. The resultant datasets and candidates are easy to understand and often offer a wealth of information that is useful for downstream analysis. This protocol is applicable to other subcellular compartments and a wide range of test conditions.

Here, we describe a quantitative proteomics method using the technique of stable isotope labeling by amino acids in cell culture (SILAC) to analyze the effects of HIV-1 infection on host exosomal proteomes. This protocol can be easily adapted to cells under different stress or infection conditions.

SILAC basada en proteómica Caracterización de exosomas del VIH-1 en células infectadas

Proteomics is the large-scale analysis of proteins. Proteomic techniques, such as liquid chromatography tandem mass spectroscopy (LC-MS/MS), can ...

Dextran Enhances the Lentiviral Transduction Efficiency of Murine and Human Primary NK Cells

The efficient transduction of specific genes into natural killer (NK) cells has been a major challenge. Successful transductions are critical to defining the role of the gene of interest in the development, differentiation, and function of NK cells. Recent advances related to chimeric antigen receptors (CARs) in cancer immunotherapy accentuate the need for an efficient method to deliver exogenous genes to effector lymphocytes. The efficiencies of lentiviral-mediated gene transductions into primary human or mouse NK cells remain significantly low, which is a major limiting factor. Recent advances using cationic polymers, such as polybrene, show an improved gene transduction efficiency in T cells. However, these products failed to improve the transduction efficiencies of NK cells. This work shows that dextran, a branched glucan polysaccharide, significantly improves the transduction efficiency of human and mouse primary NK cells. This highly reproducible transduction methodology provides a competent tool for transducing human primary NK cells, which can vastly improve clinical gene delivery applications and thus NK cell-based cancer immunotherapy.

The goal of this study was to formulate technologies that allow for successful gene transduction in primary natural killer (NK) cells. The dextran-mediated lentiviral transduction of human or mouse primary NK cells results in higher gene expression efficiencies. This method of gene transduction will vastly improve NK cell genetic manipulation.

Dextrano mejora la eficiencia de transducción lentivirales de las células NK primaria murinas y humanas

The efficient transduction of specific genes into natural killer (NK) cells has been a major challenge. Successful transductions are critical to defining ...

Using Enhanced Green Fluorescence Protein-expressing Escherichia Coli to Assess Mouse Peritoneal Macrophage Phagocytosis

This manuscript describes a simple and reproducible method to perform a phagocytosis assay. The first part of this method involves building a pET-SUMO-EGFP vector (SUMO = small ubiquitin-like modifier) and expressing enhanced green fluorescence protein (EGFP) in Escherichia coli (BL21DE). EGFP-expressing E. coli is coincubated with macrophages for 1 h at 37 &#176;C; the negative control group is incubated on ice for the same amount of time. Then, the macrophages are ready for assessment. The advantages of this technique include its simple and straightforward steps, and phagocytosis can be measured by both flow cytometer and fluorescence microscope. The EGFP-expressing E. coli are stable and display a strong fluorescence signal even after the macrophages are fixed with paraformaldehyde. This method is not only suitable for the assessment of macrophage cell lines or primary macrophages in vitro but also suitable for the evaluation of granulocyte and monocyte phagocytosis in peripheral blood mononuclear cells. The results show that the phagocytic capability of peritoneal macrophages from young (eight-week-old) mice is higher than that of macrophages from aged (16-month-old) mice. In summary, this method measures macrophage phagocytosis and is suitable for studying the innate immune system function.

Using Enhanced Green Fluorescence Protein-expressing Escherichia Coli to Assess Mouse Peritoneal Macrophage Phagocytosis

Here, we present a protocol to assess mouse peritoneal macrophage phagocytosis using enhanced green fluorescence protein-expressing Escherichia coli.

Utilizando mayor expresión de proteína de fluorescencia verde Escherichia Coli evaluar fagocitosis de macrófagos peritoneales de ratón

This manuscript describes a simple and reproducible method to perform a phagocytosis assay. The first part of this method involves building a ...

Identification of Nucleolar Factors During HIV-1 Replication Through Rev Immunoprecipitation and Mass Spectrometry

The HIV-1 infectious cycle requires viral protein interactions with host factors to facilitate viral replication, packaging, and release. The infectious cycle further requires the formation of viral/host protein complexes with HIV-1 RNA to regulate the splicing and enable nucleocytoplasmic transport. The HIV-1 Rev protein accomplishes the nuclear export of HIV-1 mRNAs through multimerization with intronic cis-acting targets - the Rev response element (RRE). A nucleolar localization signal (NoLS) exists within the COOH-terminus of the Rev arginine-rich motif (ARM), allowing the accumulation of Rev/RRE complexes in the nucleolus. Nucleolar factors are speculated to support the HIV-1 infectious cycle through various other functions in addition to mediating mRNA-independent nuclear export and splicing. We describe an immunoprecipitation method of wild-type (WT) Rev in comparison to Rev nucleolar mutations (deletion and single-point Rev-NoLS mutations) in the presence of HIV-1 replication for mass spectrometry. Nucleolar factors implicated in the nucleocytoplasmic transport (nucleophosmin B23 and nucleolin C23), as well as cellular splicing factors, lose interaction with Rev in the presence of Rev-NoLS mutations. Various other nucleolar factors, such as snoRNA C/D box 58, are identified to lose interaction with Rev mutations, yet their function in the HIV-1 replication cycle remain unknown. The results presented here demonstrate the use of this approach for the identification of viral/host nucleolar factors that maintain the HIV-1 infectious cycle. The concepts used in this approach are applicable to other viral and disease models requiring the characterization of understudied pathways.

Here we describe Rev immunoprecipitation in the presence of HIV-1 replication for mass spectrometry. The methods described can be used for the identification of nucleolar factors involved in the HIV-1 infectious cycle and are applicable to other disease models for the characterization of understudied pathways.

Identificación de factores nucleolares durante la replicación del VIH-1 a través de la inmunoprecipitación de rev y la espectrometría de masas

The HIV-1 infectious cycle requires viral protein interactions with host factors to facilitate viral replication, packaging, and release. The infectious ...