Zhong-Min Ma

Publications of Zhong-Min Ma

• Antiviral antibodies and T cells are present in the foreskin of SIV-infected rhesus macaques.

  Authors: Kristina Rothaeusler, Zhong-Min Ma, Huma Qureshi, Timothy D Carroll, Tracy Rourke, Michael B McChesney, Christopher J Miller

  Journal of virology. 04/2012;

  No information exists regarding immune responses to HIV infection in the foreskin or glans of the human penis although this is a key tissue for HIV transmission. To address this gap, we characterizedNo information exists regarding immune responses to HIV infection in the foreskin or glans of the human penis although this is a key tissue for HIV transmission. To address this gap, we characterized antiviral immune responses in foreskin of male rhesus macaques (RM) inoculated with SIVmac251 by penile foreskin exposure. We found a complete population of immune cells in the foreskin and glans of normal RM although B cells were less common than CD4(+) and CD8(+) T cells. IgG secreting cells were detected by ELISPOT in cell suspensions made from the foreskin. In the foreskin and glans of SIV-infected RM although B cells were less common than CD4(+) and CD8(+) T cells, SIV-specific IgG antibody was present in foreskin secretions. In addition, cytokine secreting SIV-specific CD8+ T cells were readily found in cell suspensions made from the foreskin. Although potential HIV target cells were found in and under the epithelium covering all penile surfaces, the presence of antiviral effector B and T cells in the foreskin suggests that vaccines may be able to elicit immunity in this critical site to protect men from acquiring HIV.

• Targeting the vaginal mucosa with human papillomavirus pseudovirion vaccines delivering simian immunodeficiency virus DNA.

  Authors: Shari N Gordon, Rhonda C Kines, Galyna Kutsyna, Zhong-Min Ma, Anna Hryniewicz, Jeffery N Roberts, Claudio Fenizia, Rachmat Hidajat, Egidio Brocca-Cofano, Nicolas Cuburu, Christopher B Buck, Marcelino L Bernardo, Marjorie Robert-Guroff, Christopher J Miller, Barney S Graham, Douglas R Lowy, John T Schiller, Genoveffa Franchini

  Journal of immunology (Baltimore, Md. : 1950). 12/2011; 188(2):714-23.

  The majority of HIV infections occur via mucosal transmission. Vaccines that induce memory T and B cells in the female genital tract may prevent the establishment and systemic dissemination of HIV.The majority of HIV infections occur via mucosal transmission. Vaccines that induce memory T and B cells in the female genital tract may prevent the establishment and systemic dissemination of HIV. We tested the immunogenicity of a vaccine that uses human papillomavirus (HPV)-based gene transfer vectors, also called pseudovirions (PsVs), to deliver SIV genes to the vaginal epithelium. Our findings demonstrate that this vaccine platform induces gene expression in the genital tract in both cynomolgus and rhesus macaques. Intravaginal vaccination with HPV16, HPV45, and HPV58 PsVs delivering SIV Gag DNA induced Gag-specific Abs in serum and the vaginal tract, and T cell responses in blood, vaginal mucosa, and draining lymph nodes that rapidly expanded following intravaginal exposure to SIV(mac251.) HPV PsV-based vehicles are immunogenic, which warrant further testing as vaccine candidates for HIV and may provide a useful model to evaluate the benefits and risks of inducing high levels of SIV-specific immune responses at mucosal sites prior to SIV infection.

• Low-dose penile SIVmac251 exposure of rhesus macaques infected with adenovirus type 5 (Ad5) and then immunized with a replication-defective Ad5-based SIV gag/pol/nef vaccine recapitulates the results of the phase IIb step trial of a similar HIV-1 vaccine.

  Authors: Huma Qureshi, Zhong-Min Ma, Ying Huang, Gregory Hodge, Michael A Thomas, Janet DiPasquale, Veronique DeSilva, Linda Fritts, Andrew J Bett, Danilo R Casimiro, John W Shiver, Marjorie Robert-Guroff, Michael N Robertson, Michael B McChesney, Peter B Gilbert, Christopher J Miller

  Journal of virology. 12/2011; 86(4):2239-50.

  The Step Trial showed that the MRKAd5 HIV-1 subtype B Gag/Pol/Nef vaccine did not protect men from HIV infection or reduce setpoint plasma viral RNA (vRNA) levels but, unexpectedly, it did modestlyThe Step Trial showed that the MRKAd5 HIV-1 subtype B Gag/Pol/Nef vaccine did not protect men from HIV infection or reduce setpoint plasma viral RNA (vRNA) levels but, unexpectedly, it did modestly enhance susceptibility to HIV infection in adenovirus type 5 (Ad5)-seropositive, uncircumcised men. As part of the process to understand the results of the Step Trial, we designed a study to determine whether rhesus macaques chronically infected with a host-range mutant Ad5 (Ad5hr) and then immunized with a replication defective Ad5 SIVmac239 Gag/Pol/Nef vaccine were more resistant or susceptible to SIV infection than unimmunized rhesus macaques challenged with a series of escalating dose penile exposures to SIVmac 251. The Ad5 SIV vaccine induced CD8(+) T cell responses in 70% of the monkeys, which is similar to the proportion of humans that responded to the vaccine in the Step Trial. However, the vaccine did not protect vaccinated animals from penile SIV challenge. At the lowest SIV exposure dose (10(3) 50% tissue culture infective doses), 2 of 9 Ad5-seropositive animals immunized with the Ad5 SIV vaccine became infected compared to 0 of 34 animals infected in the other animal groups (naive animals, Ad5-seropositive animals immunized with the empty Ad5 vector, Ad5-seronegative animals immunized with the Ad5 SIV vaccine, and Ad5-seronegative animals immunized with the empty Ad5 vector). Penile exposure to more concentrated virus inocula produced similar rates of infection in all animal groups. Although setpoint viral loads were unaffected in Step vaccinees, the Ad5 SIV-immunized animals had significantly lower acute-phase plasma vRNA levels compared to unimmunized animals. Thus, the results of the nonhuman primate (NHP) study described here recapitulate the lack of protection against HIV acquisition seen in the Step Trial and suggest a greater risk of infection in the Ad5-seropositive animals immunized with the Ad5 SIV vaccine. Further studies are necessary to confirm the enhancement of virus acquisition and to discern associated mechanisms.

• TRIM5α does not affect simian immunodeficiency virus SIV(mac251) replication in vaccinated or unvaccinated Indian rhesus macaques following intrarectal challenge exposure.

  Authors: Claudio Fenizia, Brandon F Keele, David Nichols, Stefano Cornara, Nicolò Binello, Monica Vaccari, Poonam Pegu, Marjorie Robert-Guroff, Zhong-Min Ma, Christopher J Miller, David Venzon, Vanessa Hirsch, Genoveffa Franchini

  Journal of virology. 09/2011; 85(23):12399-409.

  TRIM5α is a natural resistance factor that binds retroviral capsid proteins and restricts virus replication. The B30.2/SPRY domain of TRIM5α is polymorphic in rhesus macaques, and some alleles areTRIM5α is a natural resistance factor that binds retroviral capsid proteins and restricts virus replication. The B30.2/SPRY domain of TRIM5α is polymorphic in rhesus macaques, and some alleles are associated with reduced simian immunodeficiency virus (SIV) SIV(mac251) and SIV(smE543) replication in vivo. We determined the distribution of TRIM5α alleles by PCR and sequence analysis of the B30.2/SPRY domain in a cohort of 82 macaques. Thirty-nine of these macaques were mock vaccinated, 43 were vaccinated with either DNA-SIV/ALVAC-SIV/gp120, ALVAC-SIV/gp120, or gp120 alone, and all were exposed intrarectally to SIV(mac251) at one of three doses. We assessed whether the TRIM5α genotype of the macaques affected the replication of challenge virus by studying the number of SIV variants transmitted, the number of exposures required, the SIV(mac251) viral level in plasma and tissue, and the CD4(+) T-cell counts. Our results demonstrated that TRIM5α alleles, previously identified as restrictive for SIV(mac251) replication in vivo following intravenous exposure, did not affect SIV(mac251) replication following mucosal exposure, regardless of prior vaccination, challenge dose, or the presence of the protective major histocompatibility complex alleles (MamuA01(+), MamuB08(+), or MamuB017(+)). The TRIM5α genotype had no apparent effect on the number of transmitted variants or the number of challenge exposures necessary to infect the animals. DNA sequencing of the SIV(mac251) Gag gene of the two stocks used in our study revealed SIV(mac239)-like sequences that are predicted to be resistant to TRIM5α restriction. Thus, the TRIM5α genotype does not confound results of mucosal infection of rhesus macaques with SIV(mac251).

• SIVmac251 is inefficiently transmitted to rhesus macaques by penile inoculation with a single SIVenv variant found in ramp-up phase plasma.

  Authors: Zhong-Min Ma, Brandon F Keele, Huma Qureshi, Mars Stone, Veronique Desilva, Linda Fritts, Jeffrey D Lifson, Christopher J Miller

  AIDS research and human retroviruses. 07/2011; 27(12):1259-69.

  Abstract Despite the fact that approximately half of all HIV patients acquire infection through penile exposure, there have been no recent studies of penile SIV transmission in rhesus macaques andAbstract Despite the fact that approximately half of all HIV patients acquire infection through penile exposure, there have been no recent studies of penile SIV transmission in rhesus macaques and the nature of the virus variants transmitted, target cells, and pathways of virus dissemination to systemic lymphoid tissues are not known. Single genome amplification (SGA) and sequencing of HIV-1 RNA in plasma of acutely infected humans allows the identification and enumeration of transmitted/founder viruses responsible for productive systemic infection. Studies using the SGA strategy have shown that intrarectal and intravaginal SIV transmission to macaques recapitulates key features of human HIV transmission. To date, no studies have used the SGA assay to identify transmitted/founder virus(es) in macaques infected after penile SIV exposure. Here we report that SIV can be transmitted by penile SIV exposure. However, similar exposure to a high-dose inoculum infects only about half the animals, which is about 50% less efficient transmission than occurs after vaginal SIV challenge. In addition, only a single SIV env variant established the systemic infection in all five animals that became infected after penile exposure, a result that is consistent with low incidence and few transmitted HIV variants in heterosexually infected men. Our results suggest that the penile transmission of SIVmac251 in rhesus macaques recapitulates the key features of penile HIV-1 transmission and may provide insight into host or viral factors that permit penile transmission and dissemination. Furthermore, this SIV challenge exposure route will be useful in testing vaccines and other prophylactic approaches.

• Molecular characterization of stool microbiota in HIV-infected subjects by panbacterial and order-level 16S ribosomal DNA (rDNA) quantification and correlations with immune activation.

  Authors: Collin L Ellis, Zhong-Min Ma, Surinder K Mann, Chin-Shang Li, Jian Wu, Thomas H Knight, Tammy Yotter, Timothy L Hayes, Archana H Maniar, Paolo V Troia-Cancio, Heather A Overman, Natalie J Torok, Anthony Albanese, John C Rutledge, Christopher J Miller, Richard B Pollard, David M Asmuth

  Journal of acquired immune deficiency syndromes (1999). 03/2011; 57(5):363-70.

  The relationship between gut microbial community composition at the higher-taxonomic order level and local and systemic immunologic abnormalities in HIV disease may provide insight into how bacterialThe relationship between gut microbial community composition at the higher-taxonomic order level and local and systemic immunologic abnormalities in HIV disease may provide insight into how bacterial translocation impacts HIV disease. Antiretroviral-naive patients with HIV underwent upper endoscopy before and 9 months after starting antiretroviral treatment. Duodenal tissue was paraffin-embedded for immunohistochemical analysis and digested for fluorescence activated cell sorting for T-cell subsets and immune activation (CD38+/HLA-DR+) enumeration. Stool samples were provided from patients and control subjects for comparison. Metagenomic microbial DNA was extracted from feces for optimized 16S ribosomal RNA gene (rDNA) real-time quantitative polymerase chain reaction assays designed to quantify panbacterial loads and the relative abundances of proinflammatory Enterobacteriales order and the dominant Bacteroidales and Clostridiales orders. Samples from 10 HIV subjects before initiating and from six subjects receiving antiretroviral treatment were available for analysis. There was a trend for a greater proportion of Enterobacteriales in HIV-positive subjects compared with control subjects (P = 0.099). There were significant negative correlations between total bacterial load and duodenal CD4 and CD8 T-cell activation levels (r = -0.74, P = 0.004 and r = -0.67, P = 0.013, respectively). The proportions of Enterobacteriales and Bacteroidales were significantly correlated with duodenal CD4 T-cell depletion and peripheral CD8 T-cell activation, respectively. These data represent the first report of quantitative molecular and cellular correlations between total/universal and order-level gut bacterial populations and gastrointestinal-associated lymphoid tissue levels of immune activation in HIV-infected subjects. The correlations between lower overall 16S rDNA levels and tissue immune activation suggest that the gut microbiome may contribute to immune activation and influence HIV progression.

• A limited number of simian immunodeficiency virus (SIV) env variants are transmitted to rhesus macaques vaginally inoculated with SIVmac251.

  Authors: Mars Stone, Brandon F Keele, Zhong-Min Ma, Elizabeth Bailes, Joseph Dutra, Beatrice H Hahn, George M Shaw, Christopher J Miller

  Journal of virology. 07/2010; 84(14):7083-95.

  Single-genome amplification (SGA) and sequencing of HIV-1 RNA in plasma of acutely infected humans allows the identification and enumeration of transmitted/founder viruses responsible for productiveSingle-genome amplification (SGA) and sequencing of HIV-1 RNA in plasma of acutely infected humans allows the identification and enumeration of transmitted/founder viruses responsible for productive systemic infection. Use of this strategy as a means for identifying transmitted viruses suggested that intrarectal simian immunodeficiency virus (SIV) inoculation of macaques recapitulates key features of human rectal infection. However, no studies have used the SGA strategy to identify vaginally transmitted virus(es) in macaques or to determine how early SIV diversification in vaginally infected animals compares with HIV-1 in humans. We used SGA to amplify 227 partial env sequences from a SIVmac251 challenge stock and from seven rhesus macaques at the earliest plasma viral RNA-positive time point after low- and high-dose intravaginal inoculation. Sequences were analyzed phylogenetically to determine the relationship of transmitted/founder viruses within and between each animal and the challenge stock. In each animal, discrete low-diversity env sequence lineages were evident, and these coalesced phylogenetically to identical or near-identical env sequences in the challenge stock, thus confirming the validity of the SGA sequencing and modeling strategy for identifying vaginally transmitted SIV. Between 1 and 10 viruses were responsible for systemic infection, similar to humans infected by sexual contact, and the set of viruses transmitted to the seven animals studied represented the full genetic constellation of the challenge stock. These findings recapitulate many of the features of sexual HIV-1 transmission in women. Furthermore, the SIV rhesus macaque model can be used to understand the factors that influence the transmission of single versus multiple SIV variants.

• Preexisting infection with human T-cell lymphotropic virus type 2 neither exacerbates nor attenuates simian immunodeficiency virus SIVmac251 infection in macaques.

  Authors: Shari N Gordon, Anna R Weissman, Valentina Cecchinato, Claudio Fenizia, Zhong-Min Ma, Tzong-Hae Lee, Lorenzo Zaffiri, Vibeke Andresen, Robyn Washington Parks, Kathryn S Jones, Jean Michel Heraud, Maria Grazia Ferrari, Hye Kyung Chung, David Venzon, Renaud Mahieux, Edward L Murphy, Steven Jacobson, Christopher J Miller, Francis W Ruscetti, Genoveffa Franchini

  Journal of virology. 03/2010; 84(6):3043-58.

  Coinfection with human T-cell lymphotropic virus type 2 (HTLV-2) and human immunodeficiency virus type 1 (HIV-1) has been reported to have either a slowed disease course or to have no effect onCoinfection with human T-cell lymphotropic virus type 2 (HTLV-2) and human immunodeficiency virus type 1 (HIV-1) has been reported to have either a slowed disease course or to have no effect on progression to AIDS. In this study, we generated a coinfection animal model and investigated whether HTLV-2 could persistently infect macaques, induce a T-cell response, and impact simian immunodeficiency virus SIV(mac251)-induced disease. We found that inoculation of irradiated HTLV-2-infected T cells into Indian rhesus macaques elicited humoral and T-cell responses to HTLV-2 antigens at both systemic and mucosal sites. Low levels of HTLV-2 provirus DNA were detected in the blood, lymphoid tissues, and gastrointestinal tracts of infected animals. Exposure of HTLV-2-infected or naïve macaques to SIV(mac251) demonstrated comparable levels of SIV(mac251) viral replication, similar rates of mucosal and peripheral CD4(+) T-cell loss, and increased T-cell proliferation. Additionally, neither the magnitude nor the functional capacity of the SIV-specific T-cell-mediated immune response was different in HTLV-2/SIV(mac251) coinfected animals versus SIV(mac251) singly infected controls. Thus, HTLV-2 targets mucosal sites, persists, and importantly does not exacerbate SIV(mac251) infection. These data provide the impetus for the development of an attenuated HTLV-2-based vectored vaccine for HIV-1; this approach could elicit persistent mucosal immunity that may prevent HIV-1/SIV(mac251) infection.

• TSLP production by epithelial cells exposed to immunodeficiency virus triggers DC-mediated mucosal infection of CD4+ T cells.

  Authors: Danielle Fontenot, Hong He, Shino Hanabuchi, Pramod N Nehete, Minying Zhang, Mikyoung Chang, Bharti Nehete, Yui-Hsi Wang, Yi-Hong Wang, Zhong-Min Ma, Hai-Chon Lee, Steven F Ziegler, Amy N Courtney, Christopher J Miller, Shao-Cong Sun, Yong-Jun Liu, K Jagannadha Sastry

  Proceedings of the National Academy of Sciences of the United States of America. 09/2009; 106(39):16776-81.

  Mucosal dendritic cells have been implicated in the capture, storage, and transmission of HIV to CD4(+) T cells as well as in the promotion of HIV replication in activated CD4(+) T cells during theMucosal dendritic cells have been implicated in the capture, storage, and transmission of HIV to CD4(+) T cells as well as in the promotion of HIV replication in activated CD4(+) T cells during the cognate T-cell and DC interaction. We report that HIV induces human genital mucosal epithelial cells to produce thymic stromal lymphopoietin (TSLP) via activation of the NFkappaB signaling pathway. The TSLP secreted by HIV exposed epithelial cells activated DC, which promoted proliferation and HIV-1 replication of co-cultured autologous CD4(+) T cells. In rhesus macaques, we observed dramatic increases in TSLP expression concurrent with an increase in viral replication in the vaginal tissues within the first 2 weeks after vaginal SIV exposure. These data suggest that HIV-mediated TSLP production by mucosal epithelial cells is a critical trigger for DC-mediated amplification of HIV-infection in activated CD4(+) T cells. The cross talk between mucosal epithelial cells and DC, mediated by HIV-induced TSLP, may be an important mechanism for the high rate of HIV infection in women through the vaginal mucosa.

• Limited dissemination of pathogenic SIV after vaginal challenge of rhesus monkeys immunized with a live, attenuated lentivirus.

  Authors: Mars Stone, Zhong-Min Ma, Meritxell Genescà, Linda Fritts, Shelley Blozois, Michael B McChesney, Christopher J Miller

  Virology. 08/2009;

  In non-human primate models of AIDS, attenuated lentiviruses provide the most reliable protection from challenge with pathogenic virus but the extent to which the vaccine virus replicates afterIn non-human primate models of AIDS, attenuated lentiviruses provide the most reliable protection from challenge with pathogenic virus but the extent to which the vaccine virus replicates after challenge is unclear. At 7 and 14 days after vaginal challenge with pathogenic SIVmac239, plasma SIVenv RNA levels were significantly lower in female macaques immunized 6 months earlier with live, attenuated SHIV89.6 compared to unimmunized control animals. In 2 SHIV-immunized, unprotected macaques SIV replication produced moderate-level plasma viremia with dissemination of challenge virus to all tissues on day 14 after challenge. In protected, SHIV-immunized monkeys, SIV replication was controlled in all tissues, from the day of challenge through 14 days post-challenge. Further, in CD8(+) T cell-depleted SHIV-immunized animals, SIV replication and dissemination were more rapid than in control animals. These findings suggest that replication of a pathogenic AIDS virus can be controlled at the site of mucosal inoculation by live-attenuated lentivirus immunization.

• Critical loss of the balance between Th17 and T regulatory cell populations in pathogenic SIV infection.

  Authors: David Favre, Sharon Lederer, Bittoo Kanwar, Zhong-Min Ma, Sean Proll, Zeljka Kasakow, Jeff Mold, Louise Swainson, Jason D Barbour, Carole R Baskin, Robert Palermo, Ivona Pandrea, Christopher J Miller, Michael G Katze, Joseph M McCune

  PLoS pathogens. 03/2009; 5(2):e1000295.

  Chronic immune activation and progression to AIDS are observed after SIV infection in macaques but not in natural host primate species. To better understand this dichotomy, we compared acuteChronic immune activation and progression to AIDS are observed after SIV infection in macaques but not in natural host primate species. To better understand this dichotomy, we compared acute pathogenic SIV infection in pigtailed macaques (PTs) to non-pathogenic infection in African green monkeys (AGMs). SIVagm-infected PTs, but not SIVagm-infected AGMs, rapidly developed systemic immune activation, marked and selective depletion of IL-17-secreting (Th17) cells, and loss of the balance between Th17 and T regulatory (Treg) cells in blood, lymphoid organs, and mucosal tissue. The loss of Th17 cells was found to be predictive of systemic and sustained T cell activation. Collectively, these data indicate that loss of the Th17 to Treg balance is related to SIV disease progression.

• High Specific Infectivity of Plasma Virus from The Pre-Ramp Up and Ramp Up Stages of Acute SIV Infection.

  Authors: Zhong-Min Ma, Mars Stone, Mike Piatak, Becky Schweighardt, Nancy L. Haigwood, David Montefiori, Jeffrey D Lifson, Michael P. Busch, Christopher J Miller

  Journal of virology. 01/2009;

  To define the ratio of SIV RNA molecules to infectious virions in plasma, a ramp-up stage plasma pool was made from the earliest vRNA+ plasma samples (collected approximately 7 days afterTo define the ratio of SIV RNA molecules to infectious virions in plasma, a ramp-up stage plasma pool was made from the earliest vRNA+ plasma samples (collected approximately 7 days after inoculation) from 7 macaques and a set-point stage plasma pool from plasma samples collected 10-16 weeks after peak viremia from 7 macaques; vRNA levels in these plasma pools were determined and serial 10-fold dilutions containing from 1 to 1500 vRNA copies/mL were made. Intravenous (IV) inoculation of a 1 mL aliquot of diluted ramp-up stage plasma containing 20 vRNA copies infected 2 of 2 rhesus macaques, while for the set point stage plasma, IV inoculation with 1500 vRNA copies was needed to transmit infection. Further, when heat-inactivated set-point plasma pool was mixed with ramp-up stage virions, infection of inoculated macaques was blocked. Notably, 2 of 2 animals inoculated with 85 mL of a pre-ramp-up plasma pool containing <3 SIV RNA copies/mL developed SIV infections characterized by high levels of viral replication, demonstrating that "vRNA negative" plasma collected from macaques in the pre-ramp stage is infectious. Furthermore, there is a high ratio of infectious virions to total virions in ramp-up plasma (between 1:1 and 1:10) and a lower ratio in set-point plasma (between 1:75 and 1:750). Heat-inactivated chronic stage plasma can "neutralize" the highly infectious ramp-up stage virions. These findings have implications for understanding the natural history of SIV/HIV infection and transmission.

• Immune activation driven by CTLA-4 blockade augments viral replication at mucosal sites in simian immunodeficiency virus infection.

  Authors: Valentina Cecchinato, Elzbieta Tryniszewska, Zhong-Min Ma, Monica Vaccari, Adriano Boasso, Wen-Po Tsai, Constantinos Petrovas, Dietmar Fuchs, Jean-Michel Heraud, David Venzon, Gene M Shearer, Richard A Koup, Israel Lowy, Christopher J Miller, Genoveffa Franchini

  Journal of immunology (Baltimore, Md. : 1950). 05/2008; 180(8):5439-47.

  The importance of chronic immune activation in progression to AIDS has been inferred by correlative studies in HIV-infected individuals and in nonhuman primate models of SIV infection. Using theThe importance of chronic immune activation in progression to AIDS has been inferred by correlative studies in HIV-infected individuals and in nonhuman primate models of SIV infection. Using the SIV(mac251) macaque model, we directly address the impact of immune activation by inhibiting CTLA-4, an immunoregulatory molecule expressed on activated T cells and a subset of regulatory T cells. We found that CTLA-4 blockade significantly increased T cell activation and viral replication in primary SIV(mac251) infection, particularly at mucosal sites, and increased IDO expression and activity. Accordingly, protracted treatment with anti-CTLA-4 Ab of macaques chronically infected with SIV(mac251) decreased responsiveness to antiretroviral therapy and abrogated the ability of therapeutic T cell vaccines to decrease viral set point. These data provide the first direct evidence that immune activation drives viral replication, and suggest caution in the use of therapeutic approaches for HIV infection in vivo that increase CD4(+) T cell proliferation.

• CD8+ T-lymphocyte response to major immunodominant epitopes after vaginal exposure to simian immunodeficiency virus: too late and too little.

  Authors: Matthew R Reynolds, Eva Rakasz, Pamela J Skinner, Cara White, Kristina Abel, Zhong-Min Ma, Lara Compton, Gnankang Napoé, Nancy Wilson, Christopher J Miller, Ashley Haase, David I Watkins

  Journal of virology. 08/2005; 79(14):9228-35.

  In the acute stage of infection following sexual transmission of human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV), virus-specific CD8+ T-lymphocyte responses partiallyIn the acute stage of infection following sexual transmission of human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV), virus-specific CD8+ T-lymphocyte responses partially control but do not eradicate infection from the lymphatic tissues (LTs) or prevent the particularly massive depletion of CD4+ T lymphocytes in gut-associated lymphatic tissue (GALT). We explored hypothetical explanations for this failure to clear infection and prevent CD4+ T-lymphocyte loss in the SIV/rhesus macaque model of intravaginal transmission. We examined the relationship between the timing and magnitude of the CD8+ T-lymphocyte response to immunodominant SIV epitopes and viral replication, and we show first that the failure to contain infection is not because the female reproductive tract is a poor inductive site. We documented robust responses in cervicovaginal tissues and uterus, but only several days after the peak of virus production. Second, while we also documented a modest response in the draining genital and peripheral lymph nodes, the response at these sites also lagged behind peak virus production in these LT compartments. Third, we found that the response in GALT was surprisingly low or undetectable, possibly contributing to the severe and sustained depletion of CD4+ T lymphocytes in the GALT. Thus, the virus-specific CD8+ T-lymphocyte response is "too late and too little" to clear infection and prevent CD4+ T-lymphocyte loss. However, the robust response in female reproductive tissues may be an encouraging sign that vaccines that rapidly induce high-frequency CD8+ T-lymphocyte responses might be able to prevent acquisition of HIV-1 infection by the most common route of transmission.

• Propagation and dissemination of infection after vaginal transmission of simian immunodeficiency virus.

  Authors: Christopher J Miller, Qingsheng Li, Kristina Abel, Eun Young Kim, Zhong-Min Ma, Stephen Wietgrefe, Lisa La Franco-Scheuch, Lara Compton, Lijie Duan, Marta Dykhuizen Shore, Mary Zupancic, Marc Busch, John Carlis, Steven Wolinsky, Steven Wolinksy, Ashley T Haase

  Journal of virology. 08/2005; 79(14):9217-27.

  In the current global AIDS pandemic, more than half of new human immunodeficiency virus type 1 (HIV-1) infections are acquired by women through intravaginal HIV exposure. For this study, we exploredIn the current global AIDS pandemic, more than half of new human immunodeficiency virus type 1 (HIV-1) infections are acquired by women through intravaginal HIV exposure. For this study, we explored pathogenesis issues relevant to the development of effective vaccines to prevent infection by this route, using an animal model in which female rhesus macaques were exposed intravaginally to a high dose of simian immunodeficiency virus (SIV). We examined in detail the events that transpire from hours to a few days after intravaginal SIV exposure through week 4 to provide a framework for understanding the propagation, dissemination, and establishment of infection in lymphatic tissues (LTs) during the acute stage of infection. We show that the mucosal barrier greatly limits the infection of cervicovaginal tissues, and thus the initial founder populations of infected cells are small. While there was evidence of rapid dissemination to distal sites, we also show that continuous seeding from an expanding source of production at the portal of entry is likely critical for the later establishment of a productive infection throughout the systemic LTs. The initially small founder populations and dependence on continuous seeding to establish a productive infection in systemic LTs define a small window of maximum vulnerability for the virus in which there is an opportunity for the host, vaccines, or other interventions to prevent or control infection.

• Peak SIV replication in resting memory CD4+ T cells depletes gut lamina propria CD4+ T cells.

  Authors: Qingsheng Li, Lijie Duan, Jacob D Estes, Zhong-Min Ma, Tracy Rourke, Yichuan Wang, Cavan Reilly, John Carlis, Christopher J Miller, Ashley T Haase

  Nature. 05/2005; 434(7037):1148-52.

  In early simian immunodeficiency virus (SIV) and human immunodeficiency virus-1 (HIV-1) infections, gut-associated lymphatic tissue (GALT), the largest component of the lymphoid organ system, is aIn early simian immunodeficiency virus (SIV) and human immunodeficiency virus-1 (HIV-1) infections, gut-associated lymphatic tissue (GALT), the largest component of the lymphoid organ system, is a principal site of both virus production and depletion of primarily lamina propria memory CD4+ T cells; that is, CD4-expressing T cells that previously encountered antigens and microbes and homed to the lamina propria of GALT. Here, we show that peak virus production in gut tissues of SIV-infected rhesus macaques coincides with peak numbers of infected memory CD4+ T cells. Surprisingly, most of the initially infected memory cells were not, as expected, activated but were instead immunophenotypically 'resting' cells that, unlike truly resting cells, but like the first cells mainly infected at other mucosal sites and peripheral lymph nodes, are capable of supporting virus production. In addition to inducing immune activation and thereby providing activated CD4+ T-cell targets to sustain infection, virus production also triggered an immunopathologically limiting Fas-Fas-ligand-mediated apoptotic pathway in lamina propria CD4+ T cells, resulting in their preferential ablation. Thus, SIV exploits a large, resident population of resting memory CD4+ T cells in GALT to produce peak levels of virus that directly (through lytic infection) and indirectly (through apoptosis of infected and uninfected cells) deplete CD4+ T cells in the effector arm of GALT. The scale of this CD4+ T-cell depletion has adverse effects on the immune system of the host, underscoring the importance of developing countermeasures to SIV that are effective before infection of GALT.

• A period of transient viremia and occult infection precedes persistent viremia and antiviral immune responses during multiple low-dose intravaginal simian immunodeficiency virus inoculations.

  Authors: Zhong-Min Ma, Kristina Abel, Tracy Rourke, Yichuan Wang, Christopher J Miller

  Journal of virology. 01/2005; 78(24):14048-52.

  In rhesus macaques, classic systemic infection, characterized by persistent viremia and seroconversion, occurred after multiple low-dose (10(3) 50% tissue culture infective doses) intravaginal (IVAG)In rhesus macaques, classic systemic infection, characterized by persistent viremia and seroconversion, occurred after multiple low-dose (10(3) 50% tissue culture infective doses) intravaginal (IVAG) inoculations with simian immunodeficiency virus (SIV) strain SIVmac251. Monkeys developed classic SIV infections after a variable number of low-dose IVAG exposures to SIVmac251. Once established, the systemic infection was identical to SIV infection following high-dose IVAG SIV inoculation. However, occult systemic infection characterized by transient cell-associated or cell-free viremia consistently occurred early in the series of multiple vaginal SIV exposures. Further, antiviral cellular immune responses were present prior to the establishment of a classic systemic infection in the low-dose vaginal SIV transmission model.

• Gamma interferon-mediated inflammation is associated with lack of protection from intravaginal simian immunodeficiency virus SIVmac239 challenge in simian-human immunodeficiency virus 89.6-immunized rhesus macaques.

  Authors: Kristina Abel, Lisa La Franco-Scheuch, Tracy Rourke, Zhong-Min Ma, Veronique De Silva, Beth Fallert, Laurel Beckett, Todd A Reinhart, Christopher J Miller

  Journal of virology. 02/2004; 78(2):841-54.

  Although gamma interferon (IFN-gamma) is a key mediator of antiviral defenses, it is also a mediator of inflammation. As inflammation can drive lentiviral replication, we sought to determine theAlthough gamma interferon (IFN-gamma) is a key mediator of antiviral defenses, it is also a mediator of inflammation. As inflammation can drive lentiviral replication, we sought to determine the relationship between IFN-gamma-related host immune responses and challenge virus replication in lymphoid tissues of simian-human immunodeficiency virus 89.6 (SHIV89.6)-vaccinated and unvaccinated rhesus macaques 6 months after challenge with simian immunodeficiency virus SIVmac239. Vaccinated-protected monkeys had low tissue viral RNA (vRNA) levels, vaccinated-unprotected animals had moderate tissue vRNA levels, and unvaccinated animals had high tissue vRNA levels. The long-term challenge outcome in vaccinated monkeys was correlated with the relative balance between SIV-specific IFN-gamma T-cell responses and nonspecific IFN-gamma-driven inflammation. Vaccinated-protected monkeys had slightly increased tissue IFN-gamma mRNA levels and a high frequency of IFN-gamma-secreting T cells responding to in vitro SIVgag peptide stimulation; thus, it is likely that they could develop effective anti-SIV cytotoxic T lymphocytes in vivo. In contrast, both high tissue IFN-gamma mRNA levels and strong in vitro SIV-specific IFN-gamma T-cell responses were detected in lymphoid tissues of vaccinated-unprotected monkeys. Unvaccinated monkeys had increased tissue IFN-gamma mRNA levels but weak in vitro anti-SIV IFN-gamma T-cell responses. In addition, in lymphoid tissues of vaccinated-unprotected and unvaccinated monkeys, the increased IFN-gamma mRNA levels were associated with increased Mig/CXCL9, IP-10/CXCL10, and CXCR3 mRNA levels, suggesting that increased Mig/CXCL9 and IP-10/CXCL10 expression resulted in recruitment of CXCR3(+) activated T cells. Thus, IFN-gamma-driven inflammation promotes SIV replication in vaccinated-unprotected and unvaccinated monkeys. Unlike all unvaccinated monkeys, most monkeys vaccinated with SHIV89.6 did not develop IFN-gamma-driven inflammation, but they did develop effective antiviral CD8(+)-T-cell responses.