Association between the cytokine storm, immune cell dynamics, and viral replicative capacity in hyperacute HIV infection.

INTRODUCTION: Immunological damage in acute HIV infection (AHI) may predispose to detrimental clinical sequela. However, studies on the earliest HIV-induced immunological changes are limited, particularly in sub-Saharan Africa. We assessed the plasma cytokines kinetics, and their associations with virological and immunological parameters, in a well-characterized AHI cohort where participants were diagnosed before peak viremia. METHODS: Blood cytokine levels were measured using Luminex and ELISA assays pre-infection, during the hyperacute infection phase (before or at peak viremia, 1-11 days after the first detection of viremia), after peak viremia (24-32 days), and during the early chronic phase (77-263 days). Gag-protease-driven replicative capacities of the transmitted/founder viruses were determined using a green fluorescent reporter T cell assay. Complete blood counts were determined before and immediately following AHI detection before ART initiation. RESULTS: Untreated AHI was associated with a cytokine storm of 12 out of the 33 cytokines analyzed. Initiation of ART during Fiebig stages I-II abrogated the cytokine storm. In untreated AHI, virus replicative capacity correlated positively with IP-10 (rho = 0.84, P < 0.001) and IFN-alpha (rho = 0.59, P = 0.045) and inversely with nadir CD4+ T cell counts (rho = - 0.58, P = 0.048). Hyperacute HIV infection before the initiation of ART was associated with a transient increase in monocytes (P < 0.001), decreased lymphocytes (P = 0.011) and eosinophils (P = 0.003) at Fiebig stages I-II, and decreased eosinophils (P < 0.001) and basophils (P = 0.007) at Fiebig stages III-V. Levels of CXCL13 during the untreated hyperacute phase correlated inversely with blood eosinophils (rho = - 0.89, P < 0.001), basophils (rho = - 0.87, P = 0.001) and lymphocytes (rho = - 0.81, P = 0.005), suggesting their trafficking into tissues. In early treated individuals, time to viral load suppression correlated positively with plasma CXCL13 at the early chronic phase (rho = 0.83, P = 0.042). CONCLUSION: While commencement of ART during Fiebig stages I-II of AHI abrogated the HIV-induced cytokine storm, significant depletions of eosinophils, basophils, and lymphocytes, as well as transient expansions of monocytes, were still observed in these individuals in the hyperacute phase before the initiation of ART, suggesting that even ART initiated during the onset of viremia does not abrogate all HIV-induced immune changes.

Innate immune activation enhances hiv acquisition in women, diminishing the effectiveness of tenofovir microbicide gel.

The antiretroviral agent, tenofovir, formulated as a vaginal microbicide gel, reduces human immunodeficiency virus (HIV) acquisition by 39% in women. This study assessed the role of preexisting immune activation in HIV acquisition in women from the CAPRISA 004 trial, to identify potential strategies to increase the effectiveness of tenofovir gel. Systemic cytokine and cellular immune mediators (platelets and natural killer [NK] cells) were assessed in women at high risk for HIV assigned to either tenofovir or placebo gel in the CAPRISA 004 trial. Notwithstanding tenofovir gel use, women who acquired HIV had significantly higher systemic innate immune activation prior to infection than women who remained uninfected. Activation of both soluble (cytokine) and cellular (NK cells) immune mediators were associated with HIV acquisition, individually or in combination. Hence, an innate immune activation suppressant could be added to tenofovir gel as a potential combination gel strategy in developing the next generation of higher efficacy antiretroviral microbicides.

Broadly neutralizing antibody specificities detected in the genital tract of HIV-1 infected women.

BACKGROUND: Broadly neutralizing antibodies (bNAbs) targeting conserved epitopes on the HIV envelope glycoprotein have been identified in blood from HIV-1 infected women. We investigated whether antibodies in the genital tract from these women share similar epitope specificities and functional profiles as those in blood. METHODS: Immunoglobulin (Ig)G and IgA antibodies were isolated from cervicovaginal lavages or Softcups from 13 HIV-infected women in the CAPRISA cohort using Protein G and Peptide M, respectively. Binding antibodies to envelope antigens were quantified by ELISA and binding antibody multiplex assay. Neutralizing antibody titers and epitope targets were measured using the TZM-bl assay with Env-pseudotyped wild-type and mutated viruses. RESULTS: HIV-specific IgG, but not IgA, was detected in genital secretions and the ratio of total IgG to HIV-specific IgG was similar to plasma. HIV-specific IgG reacted with multiple envelope antigens, including V1V2, gp120, gp140 and gp41. Two women had high plasma titers of HIV-specific IgG3 which was also detected in their genital tract samples. IgG from the genital tract had neutralizing activity against both Tier 1 and Tier 2 primary HIV-isolates. Antibodies targeting well known glycan epitopes and the membrane proximal region of gp41 were detected in genital secretions, and matched specificities in plasma. CONCLUSIONS: Women with plasma bNAbs have overlapping specificities in their genital secretions, indicating that these predominantly IgG isotype antibodies may transudate from blood to the genital tract. These data provide evidence that induction of systemic HIV-specific bNAbs can lead to antiviral immunity at the portal of entry.

Compartmentalization of innate immune responses in the central nervous system during cryptococcal meningitis/HIV coinfection.

OBJECTIVE: The role of innate immunity in the pathogenesis of cryptococcal meningitis is unclear. We hypothesized that natural killer (NK) cell and monocyte responses show central nervous system (CNS) compartment-specific profiles, and are altered by antifungal therapy and combination antiretroviral therapy (cART) during cryptococcal meningitis/HIV coinfection. DESIGN: Substudy of a prospective cohort study of adults with cryptococcal meningitis/HIV coinfection in Durban, South Africa. METHODS: We used multiparametric flow cytometry to study compartmentalization of subsets, CD69 (a marker of activation), CXCR3 and CX3CR1 expression, and cytokine secretion of NK cells and monocytes in freshly collected blood and cerebrospinal fluid (CSF) at diagnosis (n = 23), completion of antifungal therapy induction (n = 19), and after a further 4 weeks of cART (n = 9). RESULTS: Relative to blood, CSF was enriched with CD56(bright) (immunoregulatory) NK cells (P = 0.0004). At enrolment, CXCR3 expression was more frequent among blood CD56(bright) than either blood CD56(dim) (P < 0.0001) or CSF CD56(bright) (P = 0.0002) NK cells. Antifungal therapy diminished blood (P < 0.05), but not CSF CXCR3(pos) NK-cell proportions nor CX3CR1(pos) NK-cell proportions. CD56(bright) and CD56(dim) NK cells were more activated in CSF than blood (P < 0.0001). Antifungal therapy induction reduced CD56(dim) NK-cell activation in CSF (P = 0.02). Activation of blood CD56(bright) and CD56(dim) NK cells was diminished following cART commencement (P < 0.0001, P = 0.03). Immunoregulatory NK cells in CSF tended to secrete higher levels of CXCL10 (P = 0.06) and lower levels of tumor necrosis factor α (P = 0.06) than blood immunoregulatory NK cells. CSF was enriched with nonclassical monocytes (P = 0.001), but antifungal therapy restored proportions of classical monocytes (P = 0.007). CONCLUSION: These results highlight CNS activation, trafficking, and function of NK cells and monocytes in cryptococcal meningitis/HIV and implicate immunoregulatory NK cells and proinflammatory monocytes as potential modulators of cryptococcal meningitis pathogenesis during HIV coinfection.