Despite the efficacy of antiretroviral therapy (ART), HIV persists in a latent form and remains a hurdle to eradication. CD4+ T lymphocytes harbor the majority of the HIV reservoir, but the role of individual subsets remains unclear. CD4+ T cells were sorted into central, transitional, effector memory, and naive T cells. We measured HIV DNA and performed proviral sequencing of more than 1900 proviruses in 2 subjects at 2 and 9 years after ART initiation to estimate the contribution of each subset to the reservoir. Although our study was limited to 2 subjects, we obtained comparable findings with publicly available sequences. While the HIV integration levels were lower in naive compared with memory T cells, naive cells were a major contributor to the intact proviral reservoir. Notably, proviral sequences isolated from naive cells appeared to be unique, while those retrieved from effector memory cells were mainly clonal. The number of clones increased as cells differentiated from a naive to an effector memory phenotype, suggesting naive cells repopulate the effector memory reservoir as previously shown for central memory cells. Naive T cells contribute substantially to the intact HIV reservoir and represent a significant hurdle for HIV eradication.
Emmanuele Venanzi Rullo, Marilia Rita Pinzone, LaMont Cannon, Sam Weissman, Manuela Ceccarelli, Ryan Zurakowski, Giuseppe Nunnari, Una O’Doherty
While the RV144 HIV vaccine trial lead to moderately reduced risk of HIV acquisition, emerging data from the repeat failure of the HVTN702 trial point to the critical need to re-examine the relationships between previously identified correlates of reduced risk of protection in the RV144 study. Specifically, the induction of V2-binding, non-IgA, IgG3 antibody responses with non-neutralizing functions were linked to reduced risk of infection in RV144 vaccinees. While each of these features was individually linked to reduced risk of infection, the relationships and interactions between these humoral immune signatures remain unclear. Thus, here we comprehensively profiled the humoral immune response in 300 RV144 vaccinees to specifically decipher the relationships between humoral biomarkers of protection and susceptibility. Here, we found that vaccine-specific IgG1, IgG3, and IgA were highly correlated. However, ratios of IgG1:IgG3:IgA provided new insights into subclass/isotype polyclonal functional regulation. For instance, in the absence of high IgG1 levels, IgG3 antibodies exhibited limited functional activity, pointing to IgG3 as a critical contributor, but not sole driver, of more effective antiviral humoral immunity. Moreover, in contrast to previous findings, higher IgA levels were linked to enhanced antibody effector function, including neutrophil phagocytosis (ADNP), complement deposition (ADCD) and NK degranulation (CD107a). Several IgA-associated functions were increased in infected vaccinees in a case:control dataset, suggesting that rather than blocking, IgA may have driven deleterious functions, thereby compromising immunity. These data highlight the interplay between IgG1, IgG3 and IgA, pointing to the critical need to deeply profile the relationships between subclass/isotype selection.
Stephanie Fischinger, Sepideh Dolatshahi, Madeleine F. Jennewein, Supachai Rerks-Ngarm, Punnee Pitisuttithum, Sorachai Nitayaphan, Nelson L. Michael, Sandhya Vasan, Margaret E Ackerman, Hendrik Streeck, Galit Alter
The integration of HIV DNA into the host genome contributes to lifelong infection in most individuals. Few studies have examined integration in lymphoid tissue, where HIV predominantly persists before and after antiretroviral treatment (ART). Of particular interest is whether integration site distributions differ between infection stages with paired blood and tissue comparisons. Here, we profiled HIV integration site distributions in sorted memory, tissue resident, and/or follicular helper CD4+ T-cell subsets from paired blood and lymphoid tissue samples from acute, chronic, and ART-treated individuals (n=3 each). We observed minor differences in the frequency of non-intronic and non-distal intergenic sites varying with tissue and residency phenotypes during ART. Genomic and epigenetic annotations were generally similar. Clonal expansion of cells marked by identical integration sites was detected, with increased detection in chronic and ART-treated individuals. However, overlap between or within CD4+ T-cell subsets or tissue compartments was only observed in 8 unique sites out of 3,540 sites studied. Together, these findings suggest that shared integration sites between blood and tissue may, depending on the tissue site, be the exception rather than the rule, and indicate that additional studies are necessary to fully understand the heterogeneity of tissue sequestered HIV reservoirs.
Vincent H. Wu, Christopher L Nobles, Leticia Kuri-Cervantes, Kevin McCormick, John K. Everett, Son Nguyen, Perla M. del Río Estrada, Mauricio González-Navarro, Santiago Ávila-Ríos, Gustavo Reyes-Terán, Frederic D. Bushman, Michael R. Betts
African green monkeys (AGMs) are natural hosts of Simian immunodeficiency virus (SIV) that post-thymically down-regulate CD4 to maintain a large population of CD4-CD8aa+ virus-resistant cells with T-helper functionality, which can result in AGMs becoming apparently cured of SIVagm infection. To understand the mechanisms of this process we performed genome-wide transcriptional analysis on T cells induced to down-regulate CD4 in vitro from AGMs and closely-related Patas monkeys, and T cells that maintain CD4 expression from rhesus macaques. In T cells that down-regulated CD4, pathway analysis revealed an atypical regulation ofthe DNA methylation machinery, which was reversible when pharmacologically targeted with 5-aza-2deoxycytidine. This signature was driven largely by the dioxygenase TET3 that became down-regulated with loss of CD4 expression. CpG motifs within the AGM CD4 promoter region became methylated during CD4 downregulation in vitro and were stably imprinted in AGM CD4-CD8aa+ T cells sorted directly ex vivo. These results suggest AGMs employ epigenetic mechanisms to durably silence the CD4 gene. Manipulation of these mechanisms could provide avenues for modulating SIV and human immunodeficiency virus (HIV)-1 entry receptor expression in hosts that become progressively SIV-infected, which could lead to novel therapeutic interventions aimed to reduce HIV viremia in vivo.
Joseph C. Mudd, Stephen Lai, Sanjana Shah, Andrew R. Rahmberg, Jacob K. Flynn, Carly E. Starke, Molly R. Perkins, Amy Ransier, Samuel Darko, Daniel Douek, Vanessa Hirsch, Mark J. Cameron, Jason M. Brenchley
Nonalcoholic fatty liver disease (NAFLD) is a common comorbidity among people living with HIV with a more aggressive course than in the general population. In a recent randomized placebo-controlled trial, we demonstrated that the growth hormone-releasing hormone analogue tesamorelin reduced liver fat and prevented fibrosis progression in HIV-associated NAFLD over one year. As such, tesamorelin is the first strategy that has shown to be effective against NAFLD among the HIV population. The current study leveraged paired liver biopsy specimens from this trial to identify hepatic gene pathways that are differentially modulated by tesamorelin versus placebo. Using Gene Set Enrichment Analysis (GSEA), we found that tesamorelin increased hepatic expression of hallmark gene sets involved in oxidative phosphorylation and decreased hepatic expression of gene sets contributing to inflammation, tissue repair, and cell division. Tesamorelin also reciprocally up- and downregulated curated gene sets associated with favorable and poor hepatocellular carcinoma prognosis, respectively. Notably, among tesamorelin-treated participants, these changes in hepatic expression correlated with improved fibrosis-related gene score. Our findings inform our knowledge of the biology of growth hormone action on the liver and provide a mechanistic basis for the observed clinical effects of tesamorelin on the liver.
Lindsay T. Fourman, James M. Billingsley, George Agyapong, Shannan J. Ho Sui, Meghan N. Feldpausch, Julia Purdy, Isabel Zheng, Chelsea S. Pan, Kathleen E. Corey, Martin Torriani, David E. Kleiner, Colleen M. Hadigan, Takara L. Stanley, Raymond T. Chung, Steven K. Grinspoon
Type I IFN (IFN-I) production by plasmacytoid DCs (pDCs) occurs during acute HIV-1 infection in response to TLR7 stimulation, but the role of pDC-derived IFN-I in controlling or promoting HIV-1 infection is ambiguous. We report here a sex-biased interferogenic phenotype for a frequent single-nucleotide polymorphism of human TLR7, rs179008, displaying an impact on key parameters of acute HIV-1 infection. We show allele rs179008 T to determine lower TLR7 protein abundance in cells from women, specifically — likely by diminishing TLR7 mRNA translation efficiency through codon usage. The hypomorphic TLR7 phenotype is mirrored by decreased TLR7-driven IFN-I production by female pDCs. Among women from the French ANRS PRIMO cohort of acute HIV-1 patients, carriage of allele rs179008 T associated with lower viremia, cell-associated HIV-1 DNA, and CXCL10 (IP-10) plasma concentrations. RNA viral load was decreased by 0.85 log10 (95% CI, −1.51 to −0.18) among T/T homozygotes, who also exhibited a lower frequency of acute symptoms. TLR7 emerges as an important control locus for acute HIV-1 viremia, and the clinical phenotype for allele rs179008 T, carried by 30%–50% of European women, supports a beneficial effect of toning down TLR7-driven IFN-I production by pDCs during acute HIV-1 infection.
Pascal Azar, José Enrique Mejía, Claire Cenac, Arnoo Shaiykova, Ali Youness, Sophie Laffont, Asma Essat, Jacques Izopet, Caroline Passaes, Michaela Müller-Trutwin, Pierre Delobel, Laurence Meyer, Jean-Charles Guéry
The RV144 HIV-1 vaccine trial results showed moderate reduction in viral infections among vaccinees as well as induction of antibody-dependent cellular cytotoxicity and vaccine-specific IgG and IgG3 responses directed at variable loop regions 1 and 2 of the HIV envelope protein. However, with the recent failure of the HVTN 702 clinical trial, comprehensive profiling of humoral immune responses may provide insight for these disappointing results. One of the changes included in the HVTN 702 study was the addition of a late boost, aimed at augmenting peak immunity and durability. The companion vaccine trial RV305 was designed to permit the evaluation of the immunologic impact of late boosting with either the boosting protein antigen alone, the canarypox viral vector ALVAC alone, or a combination of both. Although previous data showed elevated levels of IgG antibodies in both boosting arms, regardless of ALVAC-HIV vector incorporation, the effect on shaping antibody effector function remains unclear. Thus, here we analyzed the antibody and functional profile induced by RV305 boosting regimens and found that although IgG1 levels increased in both arms that included protein boosting, IgG3 levels were reduced compared with the original RV144 vaccine strategy. Most functional responses increased upon protein boosting, regardless of the viral vector-priming agent incorporation. These data suggest that the addition of a late protein boost alone is sufficient to increase functionally potent vaccine-specific antibodies previously associated with reduced risk of infection with HIV.
Stephanie Fischinger, Sally Shin, Carolyn M. Boudreau, Margaret Ackerman, Supachai Rerks-Ngarm, Punnee Pitisuttithum, Sorachai Nitayaphan, Jerome H. Kim, Merlin L. Robb, Nelson L. Michael, Robert J. O’Connell, Sandhya Vasan, Hendrik Streeck, Galit Alter
HIV-1 remains incurable due to the persistence of proviral DNA integrated into host cells, providing a reservoir for viral rebound upon cessation of antiretroviral therapy (ART). There is evidence for sex-based differences in HIV-1 immune responses and pathogenesis, but little is known about differences in HIV-1 persistence. To address this knowledge gap, we quantified persistent HIV-1 in 90 adults on suppressive ART in Rakai, Uganda (57 females). Total HIV-1 DNA was quantified by PCR and replication competent provirus by the quantitative viral outgrowth assay (QVOA). Immune phenotyping of T cell subsets and plasma biomarkers was also performed. We found that while both sexes had similar levels of total HIV DNA, females had significantly fewer cells harboring replication-competent virus, as measured by viral outgrowth in the QVOA. Predictors of viral outgrowth differed by sex; notably, frequency of PD-1+ CD4 T cells correlated with reservoir size in males, but not females. The sex-based differences in HIV-1 persistence observed in this cohort warrant additional research, especially given the widespread use of the QVOA to assess reservoir size and current explorations of PD-1 agonists in cure protocols. Efforts should be made to power future cure studies to assess outcomes in both males and females.
Jessica L. Prodger, Adam A. Capoferri, Katherine Yu, Jun Lai, Steven J. Reynolds, Jingo Kasule, Taddeo Kityamuweesi, Paul Buule, David Serwadda, Kyungyoon J. Kwon, Katherine Schlusser, Craig Martens, Eileen P. Scully, Yun-Hee Choi, Andrew D. Redd, Thomas C. Quinn
Depletion of CD4+ T cells during HIV-1 infection is mostly mediated by inflammatory cells via indirect but not clearly defined mechanisms. In this report we employed the single-cell RNA sequencing (scRNA-seq) technology to study HIV-induced transcriptomic change in innate immune cells in lymphoid organs. We performed scRNA-seq on hCD45+hCD3-hCD19- human leukocytes isolated from spleens of humanized NOD/Rag2-/-/γc-/- (NRG) mice transplanted with human CD34+ hematopoietic stem-progenitor cells (NRG-hu HSC mice). We identified major populations of innate immune cells including plasmacytoid dendritic cells (pDC), myeloid dendritic cells (mDC), macrophage, nature killer (NK) cells and innate lymphoid cells (ILC). HIV-1 infection significantly upregulated genes involved in type-I interferon inflammatory pathways in each of the innate immune subsets. Interestingly, we found that the TNF-related apoptosis-inducing ligand (TRAIL) was upregulated in the innate immune populations including pDC, mDC, macrophage, NK and ILC. We further demonstrated that blockade of TRAIL signaling pathway in NRG-hu HSC mice prevented HIV-1 induced CD4+ T cell depletion in vivo. In summary, we characterized HIV-induced transcriptomic changes of innate immune cells in the spleen at single-cell levels, identified the TRAIL+ innate immune cells and defined an important role of TRAIL signaling pathway in HIV-1 induced CD4+ T cell depletion in vivo.
Liang Cheng, Haisheng Yu, John A. Wrobel, Guangming Li, Peng Liu, Zhiyuan Hu, Xiao-Ning Xu, Lishan Su
HIV infection is associated with an increase in the proportion of activated CD8 memory T cells (Tmem) that express CX3CR1, but how these cells are generated and maintained in vivo is unclear. We demonstrate that increased CX3CR1 expression on CD8 Tmem in people living with HIV (PLWH) is dependent on coinfection with human cytomegalovirus (CMV), and CX3CR1+ CD8 Tmem are enriched for a putatively immunosenescent CD57+CD28– phenotype. The cytokine IL-15 promotes the phenotype, survival, and proliferation of CX3CR1+CD57+ CD8 Tmem in vitro, whereas TCR stimulation leads to their death. IL-15-driven survival is dependent on STAT5 and Bcl-2 activity, and IL-15-induced proliferation requires STAT5 and mTORC1. Thus, we identify mechanistic pathways that could explain how “inflammescent” CX3CR1+CD57+ CD8 Tmem dominate the overall memory T cell pool in CMV-seropositive PLWH and that support reevaluation of immune senescence as a nonproliferative dead-end.
Stephen R. Morris, Bonnie Chen, Joseph C. Mudd, Soumya Panigrahi, Carey L. Shive, Scott F. Sieg, Cheryl M. Cameron, David A. Zidar, Nicholas T. Funderburg, Souheil-Antoine Younes, Benigno Rodriguez, Sara Gianella, Michael M. Lederman, Michael L. Freeman
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