The human brain is an important site of HIV replication and persistence during antiretroviral therapy (ART). Direct evaluation of HIV infection in the brains of otherwise healthy individuals is not feasible; therefore, we performed a large-scale study of bone marrow/liver/thymus (BLT) humanized mice as an in vivo model to study HIV infection in the brain. Human immune cells, including CD4+ T cells and macrophages, were present throughout the BLT mouse brain. HIV DNA, HIV RNA, and/or p24+ cells were observed in the brains of HIV-infected animals, regardless of the HIV isolate used. HIV infection resulted in decreased numbers of CD4+ T cells, increased numbers of CD8+ T cells, and a decreased CD4+/CD8+ T cell ratio in the brain. Using humanized T cell–only mice (ToM), we demonstrated that T cells establish and maintain HIV infection of the brain in the complete absence of human myeloid cells. HIV infection of ToM resulted in CD4+ T cell depletion and a reduced CD4+/CD8+ T cell ratio. ART significantly reduced HIV levels in the BLT mouse brain, and the immune cell populations present were indistinguishable from those of uninfected controls, which demonstrated the effectiveness of ART in controlling HIV replication in the CNS and returning cellular homeostasis to a pre-HIV state.
Jenna B. Honeycutt, Baolin Liao, Christopher C. Nixon, Rachel A. Cleary, William O. Thayer, Shayla L. Birath, Michael D. Swanson, Patricia Sheridan, Oksana Zakharova, Francesca Prince, JoAnn Kuruc, Cynthia L. Gay, Chris Evans, Joseph J. Eron, Angela Wahl, J. Victor Garcia
HIV-1 acquisition occurs most commonly after sexual contact. To establish infection, HIV-1 must infect cells that support high level replication, namely CD4+ T cells, which are absent from the outermost genital epithelium. Dendritic cells (DCs), present in mucosal epithelia, potentially facilitate HIV-1 acquisition. We show that vaginal epithelial DCs, termed CD1a+ VEDCs, are unlike other blood and tissue derived DCs because they express langerin but not DC-SIGN, and unlike skin-based langerin+ DC subset, Langerhans cells (LC), they do not harbor Birbeck granules. Individuals primarily acquire HIV-1 that utilize the CCR5 receptor (termed either R5 or R5X4) during heterosexual transmission, and the mechanism for the block against variants that only use the CXCR4 receptor (classified as X4) remains unclear. We show that X4 as compared to R5 HIV-1 show limited to no replication in CD1a+ VEDCs. This differential replication occurs post-fusion suggesting that receptor usage influences post-entry steps in the virus life-cycle. Furthermore, CD1a+ VEDCs isolated from HIV-1 infected virologically suppressed women harbor HIV-1 DNA. Thus, CD1a+ VEDCs are potentially both infected early during heterosexual transmission and retain virus during treatment. Understanding the interplay between HIV-1 and CD1a+ VEDCs will be important for future prevention and cure strategies.
Victor Pena-Cruz, Luis M. Agosto, Hisashi Akiyama, Alex Olson, Yvetane Moreau, Jean-Robert Larrieux, Andrew Henderson, Suryaram Gummuluru, Manish Sagar
LN follicles constitute major reservoir sites for HIV/SIV persistence. Cure strategies could benefit from the characterization of CD8+ T cells able to access and eliminate HIV-infected cells from these areas. In this study, we provide a comprehensive analysis of the phenotype, frequency, localization, and functionality of follicular CD8+ T cells (fCD8+) in SIV-infected nonhuman primates. Although disorganization of follicles was a major factor, significant accumulation of fCD8+ cells during chronic SIV infection was also observed in intact follicles, but only in pathogenic SIV infection. In line with this, tissue inflammatory mediators were strongly associated with the accumulation of fCD8+ cells, pointing to tissue inflammation as a major factor in this process. These fCD8+ cells have cytolytic potential and can be redirected to target and kill HIV-infected cells using bispecific antibodies. Altogether, our data support the use of SIV infection to better understand the dynamics of fCD8+ cells and to develop bispecific antibodies as a strategy for virus eradication.
Sara Ferrando-Martinez, Eirini Moysi, Amarendra Pegu, Sarah Andrews, Krystelle Nganou Makamdop, David Ambrozak, Adrian B. McDermott, David Palesch, Mirko Paiardini, George N. Pavlakis, Jason M. Brenchley, Daniel Douek, John R. Mascola, Constantinos Petrovas, Richard A. Koup
Apoptosis has been proposed as a key mechanism responsible for CD4+ T cell depletion and immune dysfunction during HIV infection. We demonstrated that Q-VD-OPH, a caspase inhibitor, inhibits spontaneous and activation-induced death of T cells from SIV-infected rhesus macaques (RMs). When administered during the acute phase of infection, Q-VD-OPH was associated with (a) reduced levels of T cell death, (b) preservation of CD4+/CD8+ T cell ratio in lymphoid organs and in the gut, (c) maintenance of memory CD4+ T cells, and (d) increased specific CD4+ T cell response associated with the expression of cytotoxic molecules. Although therapy was limited to the acute phase of infection, Q-VD-OPH–treated RMs showed lower levels of both viral load and cell-associated SIV DNA as compared with control SIV-infected RMs throughout the chronic phase of infection, and prevented the development of AIDS. Overall, our data demonstrate that Q-VD-OPH injection in SIV-infected RMs may represent an adjunctive therapeutic agent to control HIV infection and delaying disease progression to AIDS.
Mireille Laforge, Ricardo Silvestre, Vasco Rodrigues, Julie Garibal, Laure Campillo-Gimenez, Shahul Mouhamad, Valérie Monceaux, Marie-Christine Cumont, Henintsoa Rabezanahary, Alain Pruvost, Anabela Cordeiro-da-Silva, Bruno Hurtrel, Guido Silvestri, Anna Senik, Jérôme Estaquier
The discovery of an HIV-1 cure remains a medical challenge because the virus rebounds quickly after the cessation of combination antiretroviral drug therapy (cART). Here, we investigate the potential of an engineered tandem bi-specific broadly neutralizing antibody (bs-bnAb) as an innovative product for HIV-1 prophylactic and therapeutic interventions. We discovered that by preserving two scFv binding domains of each parental bnAb, a single-gene-encoded tandem bs-bnAb, namely BiIA-SG, displayed significantly improved breadth and potency. BiIA-SG neutralized all 124 HIV-1 pseudotyped viruses tested, including global subtypes/recombinant forms, transmitted/founder viruses, and variants less or not susceptible to parental and many bnAbs, with an average IC50 value of 0.073 µ/ml (range < 0.001 to 1.03 µg/ml). In humanized mice, an injection of BiIA-SG conferred sterile protection when administered prior to challenges with diverse live HIV-1 stains. Moreover, while BiIA-SG delayed viral rebound in a short-term therapeutic setting when combined with cART, a single injection of AAV-transferred BiIA-SG gene resulted dose-dependently in prolonged in vivo expression of BiIA-SG, which was associated with complete viremia control and subsequent elimination of infected cells in humanized mice. These results warrant the clinical development of BiIA-SG as a promising bs-bnAb-based biomedical intervention for prevention and treatment of HIV-1 infections.
Xilin Wu, Jia Guo, Mengyue Niu, Minghui An, Li Liu, Hui Wang, Xia Jin, Qi Zhang, Ka Shing Lam, Tongjin Wu, Hua Wang, Qian Wang, Yanhua Du, Jingjing Li, Lin Cheng, Hang Ying Tang, Hong Shang, Linqi Zhang, Paul Zhou, Zhiwei Chen
HLA-B*57 control of HIV involves enhanced CD8+ T cell responses against infected cells, but extensive heterogeneity exists in level of HIV control among B*57+ individuals. Using whole genome sequencing of untreated B*57+ HIV-1 infected controllers and non-controllers, we identified a single variant (rs643347A/G) encoding an isoleucine to valine substitution at position 47 (I47V) of the inhibitory killer cell immunoglobulin-like receptor, KIR3DL1, as the only significant modifier of B*57 protection. The association replicated in an independent cohort and across multiple outcomes. The modifying effect of I47V was confined to B*57:01, and was not observed for the closely related B*57:03. Positions 2, 47, and 54 track one another nearly perfectly, and two KIR3DL1 allotypes differing only at these three positions showed significant differences in binding B*57:01 tetramers, where the protective allotype showed lower binding. Thus, variation in an immune natural killer cell receptor that binds B*57:01 modifies its protection. These data speak to exquisite specificity of KIR-HLA interactions in human health and disease.
Maureen P. Martin, Vivek Naranbhai, Patrick R. Shea, Ying Qi, Veron Ramsuran, Nicolas Vince, Xiaojiang Gao, Rasmi Thomas, Zabrina L. Brumme, Jonathan M. Carlson, Steven M. Wolinsky, James J. Goedert, Bruce D. Walker, Florencia P. Segal, Steven G. Deeks, David W. Haas, Stephen A. Migueles, Mark Connors, Nelson Michael, Jacques Fellay, Emma Gostick, Sian Llewellyn-Lacey, David A. Price, Bernard A. Lafont, Phillip Pymm, Philippa M. Saunders, Jacqueline Widjaja, Shu Cheng Wong, Julian P. Vivian, Jamie Rossjohn, Andrew G. Brooks, Mary Carrington
Eradication of HIV-1 (HIV) is hindered by stable viral reservoirs. Viral latency is epigenetically regulated. While the effects of histone acetylation and methylation at the HIV long-terminal repeat (LTR) have been described, our knowledge of the proviral epigenetic landscape is incomplete. We report that a previously unrecognized epigenetic modification of the HIV LTR, histone crotonylation, is a regulator of HIV latency. Reactivation of latent HIV was achieved following the induction of histone crotonylation through increased expression of the crotonyl-CoA–producing enzyme acyl-CoA synthetase short-chain family member 2 (ACSS2). This reprogrammed the local chromatin at the HIV LTR through increased histone acetylation and reduced histone methylation. Pharmacologic inhibition or siRNA knockdown of ACSS2 diminished histone crotonylation–induced HIV replication and reactivation. ACSS2 induction was highly synergistic in combination with either a protein kinase C agonist (PEP005) or a histone deacetylase inhibitor (vorinostat) in reactivating latent HIV. In the SIV-infected nonhuman primate model of AIDS, the expression of ACSS2 was significantly induced in intestinal mucosa in vivo, which correlated with altered fatty acid metabolism. Our study links the HIV/SIV infection–induced fatty acid enzyme ACSS2 to HIV latency and identifies histone lysine crotonylation as a novel epigenetic regulator for HIV transcription that can be targeted for HIV eradication.
Guochun Jiang, Don Nguyen, Nancie M. Archin, Steven A. Yukl, Gema Méndez-Lagares, Yuyang Tang, Maher M. Elsheikh, George R. Thompson III, Dennis J. Hartigan-O’Connor, David M. Margolis, Joseph K. Wong, Satya Dandekar
The presence of persistent, latent HIV reservoirs in CD4+ T cells obstructs current efforts to cure infection. The so-called kick-and-kill paradigm proposes to purge these reservoirs by combining latency-reversing agents with immune effectors such as cytotoxic T lymphocytes. Support for this approach is largely based on success in latency models, which do not fully reflect the makeup of latent reservoirs in individuals on long-term antiretroviral therapy (ART). Recent studies have shown that CD8+ T cells have the potential to recognize defective proviruses, which comprise the vast majority of all infected cells, and that the proviral landscape can be shaped over time due to in vivo clonal expansion of infected CD4+ T cells. Here, we have shown that treating CD4+ T cells from ART-treated individuals with combinations of potent latency-reversing agents and autologous CD8+ T cells consistently reduced cell-associated HIV DNA, but failed to deplete replication-competent virus. These CD8+ T cells recognized and potently eliminated CD4+ T cells that were newly infected with autologous reservoir virus, ruling out a role for both immune escape and CD8+ T cell dysfunction. Thus, our results suggest that cells harboring replication-competent HIV possess an inherent resistance to CD8+ T cells that may need to be addressed to cure infection.
Szu-Han Huang, Yanqin Ren, Allison S. Thomas, Dora Chan, Stefanie Mueller, Adam R. Ward, Shabnum Patel, Catherine M. Bollard, Conrad Russell Cruz, Sara Karandish, Ronald Truong, Amanda B. Macedo, Alberto Bosque, Colin Kovacs, Erika Benko, Alicja Piechocka-Trocha, Hing Wong, Emily Jeng, Douglas F. Nixon, Ya-Chi Ho, Robert F. Siliciano, Bruce D. Walker, R. Brad Jones
Type I IFN production is essential for innate control of acute viral infection; however, prolonged high-level IFN production is associated with chronic immune activation in HIV-infected individuals. Although plasmacytoid DCs (pDCs) are a primary source of IFN, the mechanisms that regulate IFN levels following the acute phase are unknown. We hypothesized that HIV-specific Ab responses regulate late IFN production. We evaluated the mechanism through which HIV-activated pDCs produce IFN as well as how both monoclonal HIV-specific Abs and Abs produced in natural HIV infection modulated normal pDC sensing of HIV. We found that HIV-induced IFN production required TLR7 signaling, receptor-mediated entry, fusion, and viral uncoating, but not endocytosis or HIV life cycle stages after uncoating. Abs directed against the HIV envelope that do not interfere with CD4 binding markedly enhanced the IFN response, irrespective of their ability to neutralize CD4+ T cell infection. Ab-mediated enhancement of IFN production required Fc γ receptor engagement, bypassed fusion, and initiated signaling through both TLR7 and TLR9, which was not utilized in the absence of Ab. Polyclonal Abs isolated from HIV-infected subjects also enhanced pDC production of IFN in response to HIV. Our data provide an explanation for high levels of IFN production and immune activation in chronic HIV infection.
Rebecca T. Veenhuis, Zachary T. Freeman, Jack Korleski, Laura K. Cohen, Guido Massaccesi, Alessandra Tomasi, Austin W. Boesch, Margaret E. Ackerman, Joseph B. Margolick, Joel N. Blankson, Michael A. Chattergoon, Andrea L. Cox
It remains controversial whether current antiretroviral therapy (ART) fully suppresses the cycles of HIV replication and viral evolution in vivo. If replication persists in sanctuary sites such as the lymph nodes, a high priority should be placed on improving ART regimes to target these sites. To investigate the question of ongoing viral replication on current ART regimens, we analyzed HIV populations in longitudinal samples from 10 HIV-1–infected children who initiated ART when viral diversity was low. Eight children started ART at less than ten months of age and showed suppression of plasma viremia for seven to nine years. Two children had uncontrolled viremia for fifteen and thirty months, respectively, before viremia suppression, and served as positive controls for HIV replication and evolution. These latter 2 children showed clear evidence of virus evolution, whereas multiple methods of analysis bore no evidence of virus evolution in any of the 8 children with viremia suppression on ART. Phylogenetic trees simulated with the recently reported evolutionary rate of HIV-1 on ART of 6 × 10–4 substitutions/site/month bore no resemblance to the observed data. Taken together, these data refute the concept that ongoing HIV replication is common with ART and is the major barrier to curing HIV-1 infection.
Gert U. Van Zyl, Mary Grace Katusiime, Ann Wiegand, William R. McManus, Michael J. Bale, Elias K. Halvas, Brian Luke, Valerie F. Boltz, Jonathan Spindler, Barbara Laughton, Susan Engelbrecht, John M. Coffin, Mark F. Cotton, Wei Shao, John W. Mellors, Mary F. Kearney