Christopher J Miller

Publications of Christopher J Miller

• 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.

• Alphavirus replicon-based adjuvants enhance the immunogenicity and effectiveness of Fluzone ® in rhesus macaques.

  Authors: Timothy D Carroll, Shannon R Matzinger, Mario Barro, Linda Fritts, Michael B McChesney, Christopher J Miller, Robert E Johnston

  Vaccine. 01/2011; 29(5):931-40.

  Venezuelan equine encephalitis virus replicon particles (VRP) without a transgene (null VRP) have been used to adjuvant effective humoral [1], cellular [2], and mucosal [3] immune responses in mice.Venezuelan equine encephalitis virus replicon particles (VRP) without a transgene (null VRP) have been used to adjuvant effective humoral [1], cellular [2], and mucosal [3] immune responses in mice. To assess the adjuvant activity of null VRP in the context of a licensed inactivated influenza virus vaccine, rhesus monkeys were immunized with Fluzone(®) alone or Fluzone(®) mixed with null VRP and then challenged with a human seasonal influenza isolate, A/Memphis/7/2001 (H1N1). Compared to Fluzone(®) alone, Fluzone(®)+null VRP immunized animals had stronger influenza-specific CD4(+) T cell responses (4.4 fold) with significantly higher levels of virus-specific IFN-γ (7.6 fold) and IL-2 (5.3 fold) producing CD4+ T cells. Fluzone(®)+null VRP immunized animals also had significantly higher plasma anti-influenza IgG (p<0.0001, 1.3 log) and IgA (p<0.05, 1.2 log) levels. In fact, the mean plasma anti-influenza IgG titers after one Fluzone(®)+null VRP immunization was 1.2 log greater (p<0.04) than after two immunizations with Fluzone(®) alone. After virus challenge, only Fluzone(®)+null VRP immunized monkeys had a significantly lower level of viral replication (p<0.001) relative to the unimmunized control animals. Although little anti-influenza antibody was detected in the respiratory secretions after immunization, strong anamnestic anti-influenza IgG and IgA responses were present in secretions of the Fluzone(®)+null VRP immunized monkeys immediately after challenge. There were significant inverse correlations between influenza RNA levels in tracheal lavages and plasma anti-influenza HI and IgG anti-influenza antibody titers prior to challenge. These results demonstrate that null VRP dramatically improve both the immunogenicity and protection elicited by a licensed inactivated influenza vaccine.

• Exogenous IFN-alpha administration reduces influenza A virus replication in the lower respiratory tract of rhesus macaques.

  Authors: Shannon R Matzinger, Timothy D Carroll, Linda Fritts, Michael B McChesney, Christopher J Miller

  PloS one. 01/2011; 6(12):e29255.

  To determine the role of innate immune responses in controlling influenza A virus replication, rhesus macaques (RM) were administered pegylated IFN-alpha prior to virus challenge. Systemic andTo determine the role of innate immune responses in controlling influenza A virus replication, rhesus macaques (RM) were administered pegylated IFN-alpha prior to virus challenge. Systemic and mucosal pegylated IFN-alpha administration induced expression of the interferon-stimulated genes (ISG) MxA and OAS in the airways. RM treated with IFN-alpha 24 hours prior to influenza virus challenge had significantly lower peak vRNA levels in the trachea compared to untreated animals. In addition to blunting viral replication, IFN-alpha treatment minimized the weight loss and spike in body temperature after influenza infection of RM. These results confirm the importance of IFN-alpha induced innate immune responses in the rapid control of influenza A virus replication in primates.

• Memory B cells and CD8⁺ lymphocytes do not control seasonal influenza A virus replication after homologous re-challenge of rhesus macaques.

  Authors: Timothy D Carroll, Shannon R Matzinger, Linda Fritts, Michael B McChesney, Christopher J Miller

  PloS one. 01/2011; 6(6):e21756.

  This study sought to define the role of memory lymphocytes in the protection from homologous influenza A virus re-challenge in rhesus macaques. Depleting monoclonal antibodies (mAb) were administeredThis study sought to define the role of memory lymphocytes in the protection from homologous influenza A virus re-challenge in rhesus macaques. Depleting monoclonal antibodies (mAb) were administered to the animals prior to their second experimental inoculation with a human seasonal influenza A virus strain. Treatment with either anti-CD8α or anti-CD20 mAbs prior to re-challenge had minimal effect on influenza A virus replication. Thus, in non-human primates with pre-existing anti-influenza A antibodies, memory B cells and CD8α⁺ T cells do not contribute to the control of virus replication after re-challenge with a homologous strain of influenza A virus.

• Envelope-modified single-cycle simian immunodeficiency virus selectively enhances antibody responses and partially protects against repeated, low-dose vaginal challenge.

  Authors: Michael D Alpert, Andrew R Rahmberg, William Neidermyer, Sharon K Ng, Angela Carville, Jeremy V Camp, Robert L Wilson, Michael Piatak, Keith G Mansfield, Wenjun Li, Christopher J Miller, Jeffrey D Lifson, Pamela A Kozlowski, David T Evans

  Journal of virology. 10/2010; 84(20):10748-64.

  Immunization of rhesus macaques with strains of simian immunodeficiency virus (SIV) that are limited to a single cycle of infection elicits T-cell responses to multiple viral gene products andImmunization of rhesus macaques with strains of simian immunodeficiency virus (SIV) that are limited to a single cycle of infection elicits T-cell responses to multiple viral gene products and antibodies capable of neutralizing lab-adapted SIV, but not neutralization-resistant primary isolates of SIV. In an effort to improve upon the antibody responses, we immunized rhesus macaques with three strains of single-cycle SIV (scSIV) that express envelope glycoproteins modified to lack structural features thought to interfere with the development of neutralizing antibodies. These envelope-modified strains of scSIV lacked either five potential N-linked glycosylation sites in gp120, three potential N-linked glycosylation sites in gp41, or 100 amino acids in the V1V2 region of gp120. Three doses consisting of a mixture of the three envelope-modified strains of scSIV were administered on weeks 0, 6, and 12, followed by two booster inoculations with vesicular stomatitis virus (VSV) G trans-complemented scSIV on weeks 18 and 24. Although this immunization regimen did not elicit antibodies capable of detectably neutralizing SIV(mac)239 or SIV(mac)251(UCD), neutralizing antibody titers to the envelope-modified strains were selectively enhanced. Virus-specific antibodies and T cells were observed in the vaginal mucosa. After 20 weeks of repeated, low-dose vaginal challenge with SIV(mac)251(UCD), six of eight immunized animals versus six of six naïve controls became infected. Although immunization did not significantly reduce the likelihood of acquiring immunodeficiency virus infection, statistically significant reductions in peak and set point viral loads were observed in the immunized animals relative to the naïve control animals.

• 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.

• Antibody-mediated protection against mucosal simian-human immunodeficiency virus challenge of macaques immunized with alphavirus replicon particles and boosted with trimeric envelope glycoprotein in MF59 adjuvant.

  Authors: Susan W Barnett, Brian Burke, Yide Sun, Elaine Kan, Harold Legg, Ying Lian, Kristen Bost, Fengmin Zhou, Amanda Goodsell, Jan Zur Megede, John Polo, John Donnelly, Jeffrey Ulmer, Gillis R Otten, Christopher J Miller, Michael Vajdy, Indresh K Srivastava

  Journal of virology. 06/2010; 84(12):5975-85.

  We have previously shown that rhesus macaques were partially protected against high-dose intravenous challenge with simian-human immunodeficiency virus SHIV(SF162P4) following sequential immunizationWe have previously shown that rhesus macaques were partially protected against high-dose intravenous challenge with simian-human immunodeficiency virus SHIV(SF162P4) following sequential immunization with alphavirus replicon particles (VRP) of a chimeric recombinant VEE/SIN alphavirus (derived from Venezuelan equine encephalitis virus [VEE] and the Sindbis virus [SIN]) encoding human immunodeficiency virus type 1 HIV-1(SF162) gp140DeltaV2 envelope (Env) and trimeric Env protein in MF59 adjuvant (R. Xu, I. K. Srivastava, C. E. Greer, I. Zarkikh, Z. Kraft, L. Kuller, J. M. Polo, S. W. Barnett, and L. Stamatatos, AIDS Res. Hum. Retroviruses 22:1022-1030, 2006). The protection did not require T-cell immune responses directed toward simian immunodeficiency virus (SIV) Gag. We extend those findings here to demonstrate antibody-mediated protection against mucosal challenge in macaques using prime-boost regimens incorporating both intramuscular and mucosal routes of delivery. The macaques in the vaccination groups were primed with VRP and then boosted with Env protein in MF59 adjuvant, or they were given VRP intramuscular immunizations alone and then challenged with SHIV(SF162P4) (intrarectal challenge). The results demonstrated that these vaccines were able to effectively protect the macaques to different degrees against subsequent mucosal SHIV challenge, but most noteworthy, all macaques that received the intramuscular VRP prime plus Env protein boost were completely protected. A statistically significant association was observed between the titer of virus neutralizing and binding antibodies as well as the avidity of anti-Env antibodies measured prechallenge and protection from infection. These results highlight the merit of the alphavirus replicon vector prime plus Env protein boost vaccine approach for the induction of protective antibody responses and are of particular relevance to advancing our understanding of the potential correlates of immune protection against HIV infection at a relevant mucosal portal of entry.

• 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.

• Use of nonhuman primate models to develop mucosal AIDS vaccines.

  Authors: Meritxell Genescà, Christopher J Miller

  Current HIV/AIDS reports. 02/2010; 7(1):19-27.

  The HIV vaccines tested in the halted Step efficacy trial and the modestly successful phase 3 RV144 trial were designed to elicit strong systemic immune responses; therefore, strategies to directThe HIV vaccines tested in the halted Step efficacy trial and the modestly successful phase 3 RV144 trial were designed to elicit strong systemic immune responses; therefore, strategies to direct immune responses into mucosal sites should be tested in an effort to improve AIDS vaccine efficacy. However, as increased CD4(+) T-cell activation and recruitment to mucosal sites have the potential to enhance HIV transmission, mucosal immune responses to HIV vaccines should primarily consist of effector CD8(+) T cells and plasma cells. Controlling the level of mucosal T-cell activation may be a critical factor in developing an effective mucosal AIDS vaccine. Immunization routes and adjuvants that can boost antiviral immunity in mucosal surfaces offer a reasonable opportunity to improve AIDS vaccine efficacy. Nonhuman primate models offer the best system for preclinical evaluation of these approaches.

• Depo-provera treatment does not abrogate protection from intravenous SIV challenge in female macaques immunized with an attenuated AIDS virus.

  Authors: Meritxell Genescà, Michael B McChesney, Christopher J Miller

  PloS one. 01/2010; 5(3):e9814.

  In a previous study, progesterone treatment of female monkeys immunized with live, attenuated SHIV89.6 abrogated the generally consistent protection from vaginal simian immunodeficiency virus (SIV)In a previous study, progesterone treatment of female monkeys immunized with live, attenuated SHIV89.6 abrogated the generally consistent protection from vaginal simian immunodeficiency virus (SIV) challenge. The mechanisms responsible for the loss of protection remain to be defined. The objective of the present study was to determine whether Depo-Provera administration alters protection from intravenous SIV challenge in SHIV-immunized female macaques. Two groups of female macaques were immunized with attenuated SHIV89.6 and then challenged intravenously with SIVmac239. Four weeks before challenge, one animal group was treated with Depo-Provera, a commonly used injectable contraceptive progestin. As expected, SHIV-immunized monkeys had significantly lower peak and set-point plasma viral RNA levels compared to naïve controls, but in contrast to previously published findings with vaginal SIV challenge, the Depo-Provera SHIV-immunized animals controlled SIV replication to a similar, or even slightly greater, degree than did the untreated SHIV-immunized animals. Control of viral replication from week 4 to week 20 after challenge was more consistent in the progesterone-treated, SHIV-immunized animals than in untreated, SHIV-immunized animals. Although levels of interferon-gamma production were similar, the SIV-specific CD8(+) T cells of progesterone-treated animals expressed more functions than the anti-viral CD8(+) T cells from untreated animals. Depo-Provera did not diminish the control of viral replication after intravenous SIV challenge in female macaques immunized with a live-attenuated lentivirus. This result contrasts with the previously reported effect of Depo-Provera(R) on protection from vaginal SIV challenge and strongly implies that the decreased protection from vaginal challenge is due to effects of progesterone on the genital tract rather than to systemic effects. Further, these results demonstrate that the effects of hormonal contraceptives on vaccine efficacy need to be considered in the context of testing and use of an AIDS vaccine.

• Damaged intestinal epithelial integrity linked to microbial translocation in pathogenic simian immunodeficiency virus infections.

  Authors: Jacob D Estes, Levelle D Harris, Nichole R Klatt, Brian Tabb, Stefania Pittaluga, Mirko Paiardini, G Robin Barclay, Jeremy Smedley, Rhonda Pung, Kenneth M Oliveira, Vanessa M Hirsch, Guido Silvestri, Daniel C Douek, Christopher J Miller, Ashley T Haase, Jeffrey Lifson, Jason M Brenchley

  PLoS pathogens. 01/2010; 6(8):e1001052.

  The chronic phase of HIV infection is marked by pathological activation of the immune system, the extent of which better predicts disease progression than either plasma viral load or CD4(+) T cellThe chronic phase of HIV infection is marked by pathological activation of the immune system, the extent of which better predicts disease progression than either plasma viral load or CD4(+) T cell count. Recently, translocation of microbial products from the gastrointestinal tract has been proposed as an underlying cause of this immune activation, based on indirect evidence including the detection of microbial products and specific immune responses in the plasma of chronically HIV-infected humans or SIV-infected Asian macaques. We analyzed tissues from SIV-infected rhesus macaques (RMs) to provide direct in situ evidence for translocation of microbial constituents from the lumen of the intestine into the lamina propria and to draining and peripheral lymph nodes and liver, accompanied by local immune responses in affected tissues. In chronically SIV-infected RMs this translocation is associated with breakdown of the integrity of the epithelial barrier of the gastrointestinal (GI) tract and apparent inability of lamina propria macrophages to effectively phagocytose translocated microbial constituents. By contrast, in the chronic phase of SIV infection in sooty mangabeys, we found no evidence of epithelial barrier breakdown, no increased microbial translocation and no pathological immune activation. Because immune activation is characteristic of the chronic phase of progressive HIV/SIV infections, these findings suggest that increased microbial translocation from the GI tract, in excess of capacity to clear the translocated microbial constituents, helps drive pathological immune activation. Novel therapeutic approaches to inhibit microbial translocation and/or attenuate chronic immune activation in HIV-infected individuals may complement treatments aimed at direct suppression of viral replication.

• 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.

• Cationic lipid/DNA complexes (JVRS-100) combined with influenza vaccine (Fluzone((R))) increases antibody response, cellular immunity, and antigenically drifted protection.

  Authors: Marla Lay, Bernadette Callejo, Stella Chang, David K Hong, David B Lewis, Timothy D Carroll, Shannon Matzinger, Linda Fritts, Christopher J Miller, John F Warner, Lily Liang, Jeffery Fairman

  Vaccine. 06/2009;

  Safe and effective adjuvants for influenza vaccines that could increase both the levels of neutralizing antibody, including against drifted viral subtypes, and T-cell immunity would be a majorSafe and effective adjuvants for influenza vaccines that could increase both the levels of neutralizing antibody, including against drifted viral subtypes, and T-cell immunity would be a major advance in vaccine design. The JVRS-100 adjuvant, consisting of DOTIM/cholesterol cationic liposome-DNA complexes, is particularly promising for vaccines that require induction of high levels of antibody and T-cell immunity, including CD8(+) cytotoxic T lymphocytes (CTL). Inclusion of protein antigens with JVRS-100 results in the induction of enhanced humoral and cell-mediated (i.e., CD4(+) and CD8(+) T cells) immune responses. The JVRS-100 adjuvant combined with a split trivalent influenza vaccine (Fluzone((R))-sanofi pasteur) elicited increased antibody and T-cell responses in mice and non-human primates compared to vaccination with Fluzone((R)) alone. Mice vaccinated with JVRS-100-Fluzone((R)) and challenged with antigenically drifted strains of H1N1 (PR/8/34) and influenza B (B/Lee/40) viruses had higher grade protection, as measured by attenuation of weight loss and increased survival, compared to recipients of unadjuvanted vaccine. The results indicate that the JVRS-100 adjuvant substantially increases immunogenicity and protection from drifted-strain challenge using an existing influenza vaccine.

• Visualizing antigen-specific and infected cells in situ predicts outcomes in early viral infection.

  Authors: Qingsheng Li, Pamela J Skinner, Sang-Jun Ha, Lijie Duan, Teresa L Mattila, Aaron Hage, Cara White, Daniel L Barber, Leigh O'Mara, Peter J Southern, Cavan S Reilly, John V Carlis, Christopher J Miller, Rafi Ahmed, Ashley T Haase

  Science (New York, N.Y.). 04/2009; 323(5922):1726-9.

  In the early stages of viral infection, outcomes depend on a race between expansion of infection and the immune response generated to contain it. We combined in situ tetramer staining with in situIn the early stages of viral infection, outcomes depend on a race between expansion of infection and the immune response generated to contain it. We combined in situ tetramer staining with in situ hybridization to visualize, map, and quantify relationships between immune effector cells and their targets in tissues. In simian immunodeficiency virus infections in macaques and lymphocytic choriomeningitis virus infections in mice, the magnitude and timing of the establishment of an excess of effector cells versus targets were found to correlate with the extent of control and the infection outcome (i.e., control and clearance versus partial or poor control and persistent infection). This method highlights the importance of the location, timing, and magnitude of the immune response needed for a vaccine to be effective against agents of persistent infection, such as HIV-1.

• 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.

• The enhanced antibody responses elicited by a CpG adjuvant does not improve the protective effect of an AT-2 inactivated SIV therapeutic AIDS vaccine.

  Authors: Yichuan Wang, Shelley A Blozis, Michael Lederman, Arthur Krieg, Alan Landay, Christopher J Miller

  Clinical and vaccine immunology : CVI. 03/2009;

  The potential benefit of using unmethylated CpG-ODN as an adjuvant in a therapeutic SIV vaccine consisting of AT2-inactivated SIVmac239 was evaluated in SIV-infected rhesus macaques receivingThe potential benefit of using unmethylated CpG-ODN as an adjuvant in a therapeutic SIV vaccine consisting of AT2-inactivated SIVmac239 was evaluated in SIV-infected rhesus macaques receiving anti-retroviral therapy (ART). We hypothesized that using CpG ODN as an adjuvant in therapeutic vaccination would enhance SIV-specific immune responses and suppress SIV replication after ART was stopped. To test our hypothesis, we immunized chronically SIV-infected rhesus macaques receiving ART with one of the following therapeutic vaccines: 1) AT2-inactivated SIVmac239, 2) CpG10103+AT2 inactivated SIVmac239, 3) CpG10103 and 4) Saline. While CpG+AT2-SIVmac239 immunization significantly increased SIV-specific IgG antibody titers, the mean plasma viral RNA level in these animals after ART did not differ from saline treated animals. The AT2-inactivated SIVmac239 immunized animal group had a significantly higher mean SIV-specific IFN-gamma T cell response after 3 immunizations and lower plasma vRNA levels for 6 weeks after ART was withdrawn compared to the saline treated animal group. Compared to saline control group, the animal group treated with CpG alone had a significantly higher mean SIV-specific lymphocyte proliferation index and a higher rate of plasma vRNA rebound after ART. These results demonstrate that while the use of CpG as an adjuvant enhances SIV-specific antibody responses, this does not improve the control of SIV replication after ART is stopped. The lack of benefit may be related to the high levels of SIV-specific lymphocyte proliferation in the CpG-adjuvant group.