Topical application of entry inhibitors as "virustats" to prevent sexual transmission of HIV infection

With the continuing march of the AIDS epidemic and little hope for an effective vaccine in the near future, work to develop a topical strategy to prevent HIV infection is increasingly important. This stated, the track record of large scale "microbicide" trials has been disappointing with nonspecific inhibitors either failing to protect women from infection or even increasing HIV acquisition. Newer strategies that target directly the elements needed for viral entry into cells have shown promise in non-human primate models of HIV transmission and as these agents have not yet been broadly introduced in regions of highest HIV prevalence, they are particularly attractive for prophylaxis. We review here the agents that can block HIV cellular entry and that show promise as topical strategies or "virustats" to prevent mucosal transmission of HIV infectio

Altered Monocyte Phenotype in HIV-1 Infection Tends to Normalize with Integrase-Inhibitor-Based Antiretroviral Therapy

Background: Monocytes are increasingly implicated in the inflammatory consequences of HIV-1 disease, yet their phenotype following antiretroviral therapy (ART) initiation is incompletely defined. Here, we define more completely monocyte phenotype both prior to ART initiation and during 48 weeks of ART. Methods: Cryopreserved peripheral blood mononuclear cells (PBMCs) were obtained at baseline (prior to ART initiation) and at weeks 12, 24, and 48 of treatment from 29 patients participating in ACTG clinical trial A5248, an open label study of raltegravir/emtricitibine/tenofovir administration. For comparison, cryopreserved PBMCs were obtained from 15 HIV-1 uninfected donors, each of whom had at least two cardiovascular risk factors. Thawed samples were stained for monocyte subset markers (CD14 and CD16), HLA-DR, CCR2, CX3CR1, CD86, CD83, CD40, CD38, CD36, CD13, and CD163 and examined using flow cytometry. Results: In untreated HIV-1 infection there were perturbations in monocyte subset phenotypes, chiefly a higher frequency and density (mean fluorescence intensity–MFI) of HLA-DR (%-p = 0.004, MFI-p = .0005) and CD86 (%-p = 0.012, MFI-p = 0.005) expression and lower frequency of CCR2 (p = 0.0002) expression on all monocytes, lower CCR2 density on inflammatory monocytes (p = 0.045) when compared to the expression and density of these markers in controls’ monocytes. We also report lower expression of CX3CR1 (p = 0.014) on patrolling monocytes at baseline, compared to levels seen in controls. After ART, these perturbations tended to improve, with decreasing expression and density of HLA-DR and CD86, increasing CCR2 density on inflammatory monocytes, and increasing expression and density of CX3CR1 on patrolling monocytes. Conclusions: In HIV-1 infected patients, ART appears to attenuate the high levels of activation (HLA-DR, CD86) and to increase expression of the chemokine receptors CCR2 and CX3CR1 on monocyte populations. Circulating monocyte phenotypes are altered in untreated infection and tend to normalize with ART; the role of these cells in the inflammatory environment of HIV-1 infection warrants further study

Perforin Expression Directly Ex Vivo by HIV-Specific CD8+ T-Cells Is a Correlate of HIV Elite Control

Many immune correlates of CD8+ T-cell-mediated control of HIV replication, including polyfunctionality, proliferative ability, and inhibitory receptor expression, have been discovered. However, no functional correlates using ex vivo cells have been identified with the known ability to cause the direct elimination of HIV-infected cells. We have recently discovered the ability of human CD8+ T-cells to rapidly upregulate perforin—an essential molecule for cell-mediated cytotoxicity—following antigen-specific stimulation. Here, we examined perforin expression capability in a large cross-sectional cohort of chronically HIV-infected individuals with varying levels of viral load: elite controllers (n = 35), viremic controllers (n = 29), chronic progressors (n = 27), and viremic nonprogressors (n = 6). Using polychromatic flow cytometry and standard intracellular cytokine staining assays, we measured perforin upregulation, cytokine production, and degranulation following stimulation with overlapping peptide pools encompassing all proteins of HIV. We observed that HIV-specific CD8+ T-cells from elite controllers consistently display an enhanced ability to express perforin directly ex vivo compared to all other groups. This ability is not restricted to protective HLA-B haplotypes, does not require proliferation or the addition of exogenous factors, is not restored by HAART, and primarily originates from effector CD8+ T-cells with otherwise limited functional capability. Notably, we found an inverse relationship between HIV-specific perforin expression and viral load. Thus, the capability of HIV-specific CD8+ T-cells to rapidly express perforin defines a novel correlate of control in HIV infection

Toll-Like Receptor Ligands Induce Human T Cell Activation and Death, a Model for HIV Pathogenesis

Background: Recently, heightened systemic translocation of microbial products was found in persons with chronic HIV infection and this was linked to immune activation and CD4 + T cell homeostasis. Methodology: We examined here the effects of microbial Toll-like receptor (TLR) ligands on T cell activation in vitro. Conclusions/Findings: We show that exposure to TLR ligands results in activation of memory and effector CD4 + and CD8 + T cells. After exposure to each of 8 different ligands that activate TLRs 2, 3, 4, 5, 7, 8, and 9, CD8 + T cells are activated and gain expression of the C type lectin CD69 that may promote their retention in lymphoid tissues. In contrast, CD4 + T cells rarely increase CD69 expression but instead enter cell cycle. Despite activation and cell cycle entry, CD4 + T cells divide poorly and instead, disproportionately undergo activation-induced cell death. Systemic exposure to TLR agonists may therefore increase immune activation, effector cell sequestration in lymphoid tissues and T cell turnover. These events may contribute to the pathogenesis of immune dysfunction and CD4+ T cell losses in chronic infection with the human immunodeficiency virus

Altered Lipidome Composition Is Related to Markers of Monocyte and Immune Activation in Antiretroviral Therapy Treated Human Immunodeficiency Virus (HIV) Infection and in Uninfected Persons

Background: HIV infection and antiretroviral therapy (ART) have both been linked to dyslipidemia and increased cardiovascular disease (CVD) risk. Alterations in the composition of saturated (SaFA), monounsaturated (MUFA), and polyunsaturated (PUFA) fatty acids are related to inflammation and CVD progression in HIV-uninfected (HIV–) populations. The relationships among the lipidome and markers of monocyte and immune activation in HIV-infected (HIV+) individuals are not well understood.Methods: Concentrations of serum lipids and their fatty acid composition were measured by direct infusion-tandem mass spectrometry in samples from 20 ART-treated HIV+ individuals and 20 HIV– individuals.Results: HIV+ individuals had increased levels of free fatty acids (FFAs) with enrichment of SaFAs, including palmitic acid (16:0) and stearic acid (18:0), and these levels were directly associated with markers of monocyte (CD40, HLA-DR, TLR4, CD36) and serum inflammation (LBP, CRP). PUFA levels were reduced significantly in HIV+ individuals, and many individual PUFA species levels were inversely related to markers of monocyte activation, such as tissue factor, TLR4, CD69, and SR-A. Also in HIV+ individuals, the composition of lysophosphatidylcholine (LPC) was enriched for SaFAs; LPC species containing SaFAs were directly associated with IL-6 levels and monocyte activation. We similarly observed direct relationships between levels of SaFAs and inflammation in HIV uninfected individuals. Further, SaFA exposure altered monocyte subset phenotypes and inflammatory cytokine production in vitro.Conclusions: The lipidome is altered in ART-treated HIV infection, and may contribute to inflammation and CVD progression. Detailed lipidomic analyses may better assess CVD risk in both HIV+ and HIV– individuals than does traditional lipid profiling

Predictors of SARS-CoV-2 RNA From Nasopharyngeal Swabs and Concordance With Other Compartments in Nonhospitalized Adults With Mild to Moderate COVID-19

Background Identifying characteristics associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA shedding may be useful to understand viral compartmentalization, disease pathogenesis, and risks for viral transmission. Methods Participants were enrolled August 2020 to February 2021 in ACTIV-2/A5401, a placebo-controlled platform trial evaluating investigational therapies for mild-to-moderate coronavirus disease 2019 (COVID-19), and underwent quantitative SARS-CoV-2 RNA testing on nasopharyngeal and anterior nasal swabs, oral wash/saliva, and plasma at entry (day 0, pretreatment) and days 3, 7, 14, and 28. Concordance of RNA levels (copies/mL) across compartments and predictors of nasopharyngeal RNA levels were assessed at entry (n = 537). Predictors of changes over time were evaluated among placebo recipients (n = 265) with censored linear regression models. Results Nasopharyngeal and anterior nasal RNA levels at study entry were highly correlated (r = 0.84); higher levels of both were associated with greater detection of RNA in plasma and oral wash/saliva. Older age, White non-Hispanic race/ethnicity, lower body mass index (BMI), SARS-CoV-2 immunoglobulin G seronegativity, and shorter prior symptom duration were associated with higher nasopharyngeal RNA at entry. In adjusted models, body mass index and race/ethnicity associations were attenuated, but the association with age remained (for every 10 years older, mean nasopharyngeal RNA was 0.27 log10 copies/mL higher; P < .001). Examining longitudinal viral RNA levels among placebo recipients, women had faster declines in nasopharyngeal RNA than men (mean change, −2.0 vs −1.3 log10 copies/mL, entry to day 3; P < .001). Conclusions SARS-CoV-2 RNA shedding was concordant across compartments. Age was strongly associated with viral shedding, and men had slower viral clearance than women, which could explain sex differences in acute COVID-19 outcomes

Bamlanivimab therapy for acute COVID-19 does not blunt SARS-CoV-2-specific memory T cell responses

Despite the widespread use of SARS-CoV-2-specific monoclonal antibody (mAb) therapy for the treatment of acute COVID-19, the impact of this therapy on the development of SARS-CoV-2-specific T cell responses has been unknown, resulting in uncertainty as to whether anti-SARS-CoV-2 mAb administration may result in failure to generate immune memory. Alternatively, it has been suggested that SARS-CoV-2-specific mAb may enhance adaptive immunity to SARS-CoV-2 via a "vaccinal effect." Bamlanivimab (Eli Lilly) is a recombinant human IgG1 that was granted FDA emergency use authorization for the treatment of mild to moderate COVID-19 in those at high risk for progression to severe disease. Here, we compared SARS-CoV-2 specific CD4+ and CD8+ T cell responses of 95 individuals from the ACTIV-2/A5401 clinical trial 28 days after treatment with 700 mg bamlanivimab versus placebo. SARS-CoV-2-specific T cell responses were evaluated using activation induced marker (AIM) assays in conjunction with intracellular cytokine staining (ICS). We demonstrate that most individuals with acute COVID-19 develop SARS-CoV-2-specific T cell responses. Overall, our findings suggest that the quantity and quality of SARS-CoV-2-specific T cell memory was not diminished in individuals who received bamlanivimab for acute COVID-19. Receipt of bamlanivimab during acute COVID-19 neither diminished nor enhanced SARS-CoV-2-specific cellular immunity

Interferon-Alpha Administration Enhances CD8+ T Cell Activation in HIV Infection

Type I interferons play important roles in innate immune defense. In HIV infection, type I interferons may delay disease progression by inhibiting viral replication while at the same time accelerating disease progression by contributing to chronic immune activation.To investigate the effects of type I interferons in HIV-infection, we obtained cryopreserved peripheral blood mononuclear cell samples from 10 subjects who participated in AIDS Clinical Trials Group Study 5192, a trial investigating the activity of systemic administration of IFNα for twelve weeks to patients with untreated HIV infection. Using flow cytometry, we examined changes in cell cycle status and expression of activation antigens by circulating T cells and their maturation subsets before, during and after IFNα treatment.The proportion of CD38+HLA-DR+CD8+ T cells increased from a mean of 11.7% at baseline to 24.1% after twelve weeks of interferon treatment (p = 0.006). These frequencies dropped to an average of 20.1% six weeks after the end of treatment. In contrast to CD8+ T cells, the frequencies of activated CD4+ T cells did not change with administration of type I interferon (mean percentage of CD38+DR+ cells = 2.62% at baseline and 2.17% after 12 weeks of interferon therapy). As plasma HIV levels fell with interferon therapy, this was correlated with a "paradoxical" increase in CD8+ T cell activation (p<0.001).Administration of type I interferon increased expression of the activation markers CD38 and HLA DR on CD8+ T cells but not on CD4+ T cells of HIV+ persons. These observations suggest that type I interferons may contribute to the high levels of CD8+ T cell activation that occur during HIV infection