Adeno-associated virus (AAV)-delivered anti-HIV-1 broadly neutralizing antibodies (bNAbs) could prevent and treat HIV-1 infection but are limited by host immune responses, specifically anti-drug antibodies (ADA). We tested whether PD-L1-mediated immune shielding could improve the consistency of AAV-delivered bNAb expression from muscle tissue in rhesus macaques. AAV9.PD-L1 co-delivery with AAV9.3BNC117 reduced the occurrence of ADA and T cell responses and improved the durability of 3BNC117 expression for one year post administration. Importantly, 5 of 6 macaques that received co-delivered AAV9.PD-L1 vectors were protected against ten repeated SHIVAD8-EO challenges. Histopathological and spatial transcriptomic profiling showed that AAV9.PD-L1 co-delivery prevented severe local inflammation, muscle injury, and tertiary lymphoid structure formation at the administration site. Thus, immune shielding could serve as a strategy to prolong transgene expression from muscle-directed AAV-delivered biologics.

The anti-apoptotic molecule BCL-2 favours the maintenance of the CD4+ T-cell reservoir during HIV infection. Whether inhibition of BCL-2 can lead to long-term reduction of the HIV reservoir is unclear. Here we initiated antiretroviral therapy (ART) in 24 simian immunodeficiency virus (SIV)-infected rhesus macaques at 14 days post infection (p.i.), alone or combined with a 10-day treatment of venetoclax or venetoclax and CD8α depletion, with a follow-up to day 294 p.i. We report a rapid and sustained reduction of the intact SIV reservoir in venetoclax-treated rhesus macaques in blood and lymph nodes. CD4+ T cells that persisted after venetoclax treatment showed partial reduction in apoptotic sensitivity in ex vivo assays. These exhibited elevated expression of anti-apoptotic BCL-2 and BCL-xL, and showed reduced expression of pro-apoptotic molecules such as PUMA. These findings support the rationale for extended venetoclax dosing and suggest that combining BCL-2 inhibition with agents targeting additional anti-apoptotic molecules could enhance clearance of the viral reservoir in HIV cure strategies.

Adeno-associated virus (AAV)-delivered anti-HIV-1 broadly neutralizing antibodies (bNAbs) have demonstrated promise for preventing and treating HIV-1 infection in preclinical models. However, host immune responses, specifically anti-drug antibodies (ADA), limit sustained bNAb expression. We have previously shown that PD-L1-mediated immune shielding improves the consistency of AAV-delivered bNAb 3BNC117 expression from muscle tissue in rhesus macaques. Here, we test the breadth of this approach with another bNAb, 10-1074. We show that AAV9.PD-L1 co-delivery with AAV9.10-1074 reduced the occurrence of ADA responses and improved the durability of bNAb expression for one year post administration. Notably 12 of 12 macaques that received AAV9.10-1074 vectors were protected against ten repeated SHIVAD8-EO challenges. Histopathological profiling showed that AAV9.PD-L1 co-delivery prevented severe local inflammation and tertiary lymphoid structure formation at the administration site. Thus, immune shielding could serve as a broad strategy to prolong transgene expression from muscle-directed AAV-delivered biologics.

The establishment of a reservoir of latently infected CD4+ T cells that persist on antiretroviral therapy (ART) through proliferation represents the main barrier to HIV cure. Here, we evaluated in macaques a therapeutic approach targeting Wnt and Notch pathways that regulate T cell proliferation and differentiation during acute SIV infection, when the viral reservoir is seeded. The combination of PRI-724 and LY3039478 led to reprogramming of central memory CD4+ T cells away from quiescence and stemness toward a metabolically active effector profile resulting in reduced infection of central memory CD4+ T cells. Following sustained ART, levels of SIV RNA in CD4+ T cells were higher in the PRI-724 + LY3039478-treated group compared to controls, although SIV DNA was similar. These findings suggest that stemness pathway inhibition promotes memory T cell differentiation leading to a more transcriptionally active reservoir and has potential to synergize with "shock-and-kill" approaches to reduce HIV persistence.

Current influenza vaccines face challenges due to antigenic evolution of the circulating virus and waning immunity in humans. Here we investigated the durability of humoral immunity induced by an influenza vaccine based on AS03-adjuvanted chimeric hemagglutinin (cHA) in nonhuman primates (NHPs). Two groups of NHPs received two doses of a seasonal quadrivalent influenza vaccine, followed by sequential immunization with split virus cHA vaccines cH8/1N1, and cH5/1N1. One group received cHA immunizations with AS03 adjuvant. We monitored serum antibodies and long-lived plasma cells in bone marrow for nearly 2 years after the final vaccination. cHA vaccines induced stalk-specific antibody responses. The addition of AS03 enhanced both the magnitude and durability of humoral immunity by establishing long-lived plasma cells in the bone marrow and lymph nodes for nearly 2 years. Passive transfer of NHP serum provided protection against challenge with heterologous influenza A virus strains in mice. This study highlights the potential of the AS03-adjuvanted chimeric HA vaccine strategy to provide durable and broadly protective humoral immunity. The authors report that an AS03-adjuvanted chimeric hemagglutinin-based influenza vaccine induces persistent stalk-specific serum antibody and bone marrow plasma cell responses in nonhuman primates, offering promise for broader and durable flu protection.

Cardiomyocytes derived from human induced pluripotent stem cells (hiPSC-CMs) possess tremendous advantage for cardiac regeneration. However, cell survival challenging upon cell transplantation. Since microgravity can profoundly affect cellular properties, we investigated the effect of spaceflight on hiPSC-CMs. spheroids derived from hiPSCs were transported to the International Space Station (ISS) via the SpaceX Crew-8 mission and cultured under space microgravity days. Beating cardiac spheroids were observed on the ISS and upon successful experimentation by the astronauts in space, the live cultures were returned These cells had normal displacement (an indicator of contraction) and Ca2+ transient parameters in 3D live cell imaging. Proteomic analysis revealed that spaceflight upregulated many proteins involved in metabolism (n = 90), cellular component of mitochondrion (n = 62) and regulation of proliferation (n = 10). metabolic pathways enriched by spaceflight included glutathione metabolism, biosynthesis of amino acids, and pyruvate metabolism. In addition, the top gulated proteins in spaceflight samples included those involved in cellular stress response, cell survival, and metabolism. Transcriptomic profiles indicated spaceflight upregulated genes associated with cardiomyocyte development, and cellular components of cardiac structure and mitochondrion. Furthermore, flight upregulated genes in metabolic pathways associated with cell survival such as glycerophospholipid metabolism and glycerolipid metabolism. These indicate that short-term exposure of 3D hiPSC-CMs to the space environment led to significant changes in protein levels and gene expression involved in cell and metabolism.

Inflammatory stimuli administered to humans and laboratory animals affect mesolimbic and nigrostriatal dopaminergic pathways in association with impaired motivation and motor activity. Alterations in dopaminergic corticostriatal reward and motor circuits have also been observed in depressed patients with increased peripheral inflammatory markers. The effects of peripheral inflammation on dopaminergic pathways and associated neurobiologic mechanisms and consequences have been difficult to measure in patients. Postmortem tissue (n = 11) from an established, translationally-relevant non-human primate model of cytokine-induced depressive behavior involving chronic interferon-alpha (IFN-a) administration was utilized herein to explore the molecular mechanisms of peripheral cytokine effects on striatal dopamine. Dopamine (but not serotonin or norepinephrine) was decreased in the nucleus accumbens (NAcc) and putamen of IFN-a-treated animals (p < 0.05). IFN-a had no effect on number of striatal neurons or dopamine terminal density, suggesting no overt neurodegenerative changes. RNA sequencing examined in the caudate, putamen, substantia nigra, and prefrontal cortical subregions revealed that while IFN-a nominally up-regulated limited numbers of genes enriching inflammatory signaling pathways in all regions, robust, whole genome-significant effects of IFN-a were observed specifically in putamen. Genes upregulated in the putamen primarily enriched synaptic signaling, glutamate receptor signaling, and inflammatory/metabolic pathways downstream of IFN-a, including MAPK and PI3K/AKT cascades. Conversely, gene transcripts reduced by IFN-a enriched oxidative phosphorylation (OXPHOS), protein translation, and pathways regulated by dopamine receptors. Unsupervised clustering identified a gene co-expression module in the putamen that was associated with both IFN-a treatment and low dopamine levels, which enriched similar inflammatory, metabolic, and synaptic signaling pathways. IFN-a-induced reductions in dopamine further correlated with genes related to excitotoxic glutamate, kynurenine, and altered dopamine receptor signaling (r = 0.78-97, p < 0.05). These findings provide insight into the immunologic mechanisms and neurobiological consequences of peripheral inflammation effects on dopamine, which may inform novel treatment strategies targeting inflammatory, metabolic or neurotransmitter systems in depressed patients with high inflammation.

Intratumoral heterogeneity drives cancer progression and influences treatment outcomes. The mechanisms underlying how cellular subpopulations communicate and cooperate to impact progression remain largely unknown. Here, we use collective invasion as a model to deconstruct processes underlying non-small cell lung cancer subpopulation cooperation. We reveal that collectively invading packs consist of heterogeneously cycling and non-cycling subpopulations using distinct pathways. We demonstrate that the follower subpopulation secretes transforming growth factor beta one (TGF-β1) to stimulate divergent subpopulation responses-including proliferation, pack cohesion, and JAG1-dependent invasion-depending on cellular context. While isolated followers maintain proliferation in response to TGF-β1, isolated leaders enter a quiescence-like cellular state. In contrast, leaders within a heterogeneous population sustain proliferation to maintain subpopulation proportions. In vivo, both leader and follower subpopulations are necessary for macro-metastatic disease progression. Taken together, these findings highlight that intercellular communication preserves tumor cell heterogeneity and promotes collective behaviors such as invasion and tumor progression.

The anti-apoptotic molecule BCL-2 favors the maintenance of the CD4+ T-cell reservoir during Human Immunodeficiency Virus (HIV) infection. We investigated directly in-vivo whether BCL-2 inhibition using venetoclax at the initiation of antiretroviral therapy (ART) would reduce the size of the viral reservoir. Twenty-four SIVmac239-infected rhesus macaques (RMs) initiated ART at day 14 post-infection (p.i.), alone or with a 10-day treatment with venetoclax or venetoclax plus CD8α depletion, and followed up to day 294 p.i. A rapid, statistically significant, and sustained reduction in the intact SIV reservoir was observed in venetoclax-treated RMs in blood and lymph nodes (LNs). This reduction was driven by reduced survival and depletion of CD4+ T-cell subsets that critically contribute to the reservoir. CD4+ T-cells that persisted after venetoclax treatment exhibited elevated per-cell levels of BCL-2, reduced expression of pro-apoptotic molecules such as PUMA, increased expression of additional anti-apoptotic molecules, including BCL-xL, and a partial reduction in apoptotic sensitivity in ex vivo assays. These findings provide mechanistic insights for the venetoclax-induced pro-cell death changes in CD4+ T-cells, support the rationale for extended venetoclax dosing, and suggest that combining BCL-2 inhibition with agents targeting additional anti-apoptotic molecules can enhance clearance of the viral reservoir in HIV cure strategies.

Human immunodeficiency virus (HIV) continues to be a significant global health challenge despite decades of research and advances in treatment. Substantial gaps in our understanding of the mechanisms of HIV pathogenesis and the host immune responses still exist. The interaction between HIV and these immune responses is pivotal in the disease progression to acquired immunodeficiency syndrome (AIDS). Recently, the caspase recruitment domain-containing protein 8 (CARD8) inflammasome has emerged as a crucial factor in orchestrating innate immune responses to HIV infection and exerting a substantial impact on viral pathogenesis. CARD8 restricts viral replication by detecting the activity of HIV protease. Conversely, it also contributes to the depletion of CD4+ T cells, a key feature of disease progression towards AIDS. The purpose of this review is to summarize the role of the CARD8 inflammasome in HIV pathogenesis, delving into its mechanisms of action and potential implications for the development of therapeutic strategies.

ABSTRACT Zika virus (ZIKV) is a mosquito-borne flavivirus that caused an epidemic in the Americas in 2016 and is linked to severe neonatal birth defects, including microcephaly and spontaneous abortion. To better understand the host response to ZIKV infection, we adapted the 10× Genomics Chromium single-cell RNA sequencing (scRNA-seq) assay to simultaneously capture viral RNA and host mRNA. Using this assay, we profiled the antiviral landscape in a population of human monocyte-derived dendritic cells infected with ZIKV at the single-cell level. The bystander cells, which lacked detectable viral RNA, expressed an antiviral state that was enriched for genes coinciding predominantly with a type I interferon (IFN) response. Within the infected cells, viral RNA negatively correlated with type I IFN-dependent and -independent genes (the antiviral module). We modeled the ZIKV-specific antiviral state at the protein level, leveraging experimentally derived protein interaction data. We identified a highly interconnected network between the antiviral module and other host proteins. In this work, we propose a new paradigm for evaluating the antiviral response to a specific virus, combining an unbiased list of genes that highly correlate with viral RNA on a per-cell basis with experimental protein interaction data. IMPORTANCE Zika virus (ZIKV) remains a public health threat given its potential for re-emergence and the detrimental fetal outcomes associated with infection during pregnancy. Understanding the dynamics between ZIKV and its host is critical to understanding ZIKV pathogenesis. Through ZIKV-inclusive single-cell RNA sequencing (scRNA-seq), we demonstrate on the single-cell level the dynamic interplay between ZIKV and the host: the transcriptional program that restricts viral infection and ZIKV-mediated inhibition of that response. Our ZIKV-inclusive scRNA-seq assay will serve as a useful tool for gaining greater insight into the host response to ZIKV and can be applied more broadly to the flavivirus field.

Crosstalk between the microbiome and gut mucosa-resident immune cells plays a pivotal role in modulating immune responses to pathogens, including responses to HIV infection. However, how these interactions may differ between young men who have sex with men (YMSM) disproportionately impacted by HIV, as compared with older adult MSM (AMSM), is not well understood. A broad analysis of associations between the microbiome and rectal transcriptome revealed 10 microbial families/genera correlated with immunologic gene pathways. Specifically, the rectal transcriptome of YMSM was characterized by upregulation of T cell activation/differentiation pathways and signaling from multiple cytokine families compared with AMSM. The microbiome of YMSM was enriched with pathogenic genera, including Peptostreptococcus, shown to be positively correlated with type I IFN pathways important for antiviral immunity. These findings demonstrate that YMSM have a unique immune phenotype and rectal microenvironment and support further evaluation of biological factors that influence rectal HIV transmission.

Human immunodeficiency virus (HIV) cure efforts are increasingly focused on harnessing CD8(+) T cell functions, which requires a deeper understanding of CD8(+) T cells promoting HIV control. Here we identifiy an antigen-responsive TOX(hi)TCF1(+)CD39(+)CD8(+) T cell population with high expression of inhibitory receptors and low expression of canonical cytolytic molecules. Transcriptional analysis of simian immunodeficiency virus (SIV)-specific CD8(+) T cells and proteomic analysis of purified CD8(+) T cell subsets identified TOX(hi)TCF1(+)CD39(+)CD8(+) T cells as intermediate effectors that retained stem-like features with a lineage relationship with terminal effector T cells. TOX(hi)TCF1(+)CD39(+)CD8(+) T cells were found at higher frequency than TCF1(-)CD39(+)CD8(+) T cells in follicular microenvironments and were preferentially located in proximity of SIV-RNA(+) cells. Their frequency was associated with reduced plasma viremia and lower SIV reservoir size. Highly similar TOX(hi)TCF1(+)CD39(+)CD8(+) T cells were detected in lymph nodes from antiretroviral therapy-naive and antiretroviral therapy-suppressed people living with HIV, suggesting this population of CD8(+) T cells contributes to limiting SIV and HIV persistence.

Although effective contraceptives are crucial for preventing unintended pregnancies, evidence suggests that their use may perturb the female genital tract (FGT). A comparative analysis of the effects of the most common contraceptives on the FGT have not been evaluated in a randomized clinical trial setting. Here, we evaluated the effect of three long-acting contraceptive methods: depot medroxyprogesterone acetate(DMPA-IM), levonorgestrel(LNG) implant, and a copper intrauterine device (Cu-IUD), on the endocervical host transcriptome in 188 women from the Evidence for Contraceptive Options and HIV Outcomes Trial (ECHO) trial. Cu-IUD usage showed the most extensive transcriptomic changes, and was associated with inflammatory and anti-viral host responses. DMPA-IM usage was enriched for pathways associated with T cell responses. LNG implant had the mildest effect on endocervical gene expression, and was associated with growth factor signaling. These data provide a mechanistic basis for the diverse influence that varying contraceptives have on the FGT.

Type-I interferons (IFN-I) are critical mediators of innate control of viral infections, but also drive recruitment of inflammatory cells to sites of infection, a key feature of severe COVID-19. Here, and for the first time, IFN-I signaling was modulated in rhesus macaques (RMs) prior to and during acute SARS-CoV-2 infection using a mutated IFNα2 (IFN-modulator; IFNmod), which has previously been shown to reduce the binding and signaling of endogenous IFN-I. In SARS-CoV-2-infected RMs, IFNmod reduced both antiviral and inflammatory ISGs. Notably, IFNmod treatment resulted in a potent reduction in (i) SARS-CoV-2 viral load in Bronchoalveolar lavage (BAL), upper airways, lung, and hilar lymph nodes; (ii) inflammatory cytokines, chemokines, and CD163+MRC1-inflammatory macrophages in BAL; and (iii) expression of Siglec-1, which enhances SARS-CoV-2 infection and predicts disease severity, on circulating monocytes. In the lung, IFNmod also reduced pathogenesis and attenuated pathways of inflammasome activation and stress response during acute SARS-CoV-2 infection. This study, using an intervention targeting both IFN-α and IFN-β pathways, shows that excessive inflammation driven by type 1 IFN critically contributes to SARS-CoV-2 pathogenesis in RMs, and demonstrates the potential of IFNmod to limit viral replication, SARS-CoV-2 induced inflammation, and COVID-19 severity.

Summary: The accessory viral protein R (Vpr) is encoded by all primate lentiviruses. Vpr counteracts DNA repair pathways, modulates viral immune sensing, and induces cell-cycle arrest in cell culture. However, its impact in vivo is controversial. Here, we show that deletion of vpr is associated with delayed viral replication kinetics, rapid innate immune activation, development and maintenance of strong B and T cell responses, and increased neutralizing activity against SIVmac239 in rhesus macaques. All wild-type SIVmac239-infected animals maintained high viral loads, and five of six developed fatal immunodeficiency during ∼80 weeks of follow-up. Lack of Vpr was associated with better preservation of CD4+ T cells, lower viral loads, and an attenuated clinical course of infection in most animals. Our results show that Vpr contributes to efficient viral immune evasion and the full pathogenic potential of SIVmac in vivo. Inhibition of Vpr may improve humoral immune control of viral replication.

Route of immunization can markedly influence the quality of immune response. Here, we show that intradermal (ID) but not intramuscular (IM) modified vaccinia Ankara (MVA) vaccinations provide protection from acquisition of intravaginal tier2 simian-human immunodeficiency virus (SHIV) challenges in female macaques. Both routes of vaccination induce comparable levels of serum IgG with neutralizing and non-neutralizing activities. The protection in MVA-ID group correlates positively with serum neutralizing and antibody-dependent phagocytic activities, and envelope-specific vaginal IgA; while the limited protection in MVA-IM group correlates only with serum neutralizing activity. MVA-ID immunizations induce greater germinal center Tfh and B cell responses, reduced the ratio of Th1 to Tfh cells in blood and showed lower activation of intermediate monocytes and inflammasome compared to MVA-IM immunizations. This lower innate activation correlates negatively with induction of Tfh responses. These data demonstrate that the MVA-ID vaccinations protect against intravaginal SHIV challenges by modulating the innate and T helper responses.

The HIV reservoir is largely composed of latently infected memory CD4 + T cells that persist during antiretroviral therapy and constitute a major barrier toward HIV eradication. In particular, CD4 + T follicular helper cells have been demonstrated as key targets for viral replication and persistence under ART.