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Introduction Vaccine responses are known to vary geographically. Bacillus Calmette-Guerin (BCG) for tuberculosis (TB) is perhaps the best known example of a vaccine for which efficacy rates vary according to [...], Vaccine responses vary by geographic location. We have previously described how HIV-associated inflammation leads to fibrosis of secondary lymph nodes (LNs) and T cell depletion. We hypothesized that other infections may cause LN inflammation and fibrosis, in a process similar to that seen in HIV infection, which may lead to T cell depletion and affect vaccine responses. We studied LNs of individuals from Kampala, Uganda, before and after yellow fever vaccination (YFV) and found fibrosis in LNs that was similar to that seen in HIV infection. We found blunted antibody responses to YFV that correlated to the amount of LN fibrosis and loss of T cells, including T follicular helper cells. These data suggest that LN fibrosis is not limited to HIV infection and may be associated with impaired immunologic responses to vaccines. This may have an impact on vaccine development, especially for infectious diseases prevalent in the developing world.

Introduction The ability of [CD8.sup.+] T cells to clear virus-infected, including HIV-infected, cells depends on the ability of [CD8.sup.+] T cells to migrate to sites of active virus replication (1-3). [...], LN follicles constitute major reservoir sites for HIV/SIV persistence. Cure strategies could benefit from the characterization of [CD8.sup.+] 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.sup.+] T cells (f[CD8.sup.+]) in SIV-infected nonhuman primates. Although disorganization of follicles was a major factor, significant accumulation of f[CD8.sup.+] 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 f[CD8.sup.+] cells, pointing to tissue inflammation as a major factor in this process. These f[CD8.sup.+] 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 f[CD8.sup.+] cells and to develop bispecific antibodies as a strategy for virus eradication.

Author(s): Jacob D Estes [1]; Cissy Kityo [2]; Francis Ssali [2]; Louise Swainson [3]; Krystelle Nganou Makamdop [4]; Gregory Q Del Prete [1]; Steven G Deeks [5]; Paul A Luciw [...], In the quest for a functional cure or the eradication of HIV infection, it is necessary to know the sizes of the reservoirs from which infection rebounds after treatment interruption. Thus, we quantified SIV and HIV tissue burdens in tissues of infected nonhuman primates and lymphoid tissue (LT) biopsies from infected humans. Before antiretroviral therapy (ART), LTs contained [greater than] 98% of the SIV RNA[sup.+] and DNA[sup.+] cells. With ART, the numbers of virus (v) RNA+ cells substantially decreased but remained detectable, and their persistence was associated with relatively lower drug concentrations in LT than in peripheral blood. Prolonged ART also decreased the levels of SIV- and HIV-DNA[sup.+] cells, but the estimated size of the residual tissue burden of 10[sup.8] vDNA[sup.+] cells potentially containing replication-competent proviruses, along with evidence of continuing virus production in LT despite ART, indicated two important sources for rebound following treatment interruption. The large sizes of these tissue reservoirs underscore challenges in developing 'HIV cure' strategies targeting multiple sources of virus production.

We designed and produced an IFN-I receptor antagonist (IFN-1ant) that blocks IFN-α2 antiviral and antiproliferative activity in vitro (19). Six rhesus macaques received 1 mg of IFN-1ant daily for 4 [...], Inflammation in HIV infection is predictive of non-AIDS morbidity and death (1), higher set point plasma virus load (2) and virus acquisition (3); thus, therapeutic agents are in development to reduce its causes and consequences. However, inflammation may simultaneously confer both detrimental and beneficial effects. This dichotomy is particularly applicable to type I interferons (IFN-I) which, while contributing to innate control of infection (4-10), also provide target cells for the virus during acute infection, impair CD4 T-cell recovery, and are associated with disease progression (6,7,11-19). Here we manipulated IFN-I signalling in rhesus macaques (Macaca mulatta) during simian immunodeficiency virus (SIV) transmission and acute infection with two complementary in vivo interventions. We show that blockade of the IFN-I receptor caused reduced antiviral gene expression, increased SIV reservoir size and accelerated CD4 T-cell depletion with progression to AIDS despite decreased T-cell activation. In contrast, IFN-α2a administration initially upregulated expression of antiviral genes and prevented systemic infection. However, continued IFN-α2a treatment induced IFN-I desensitization and decreased antiviral gene expression, enabling infection with increased SIV reservoir size and accelerated CD4 T-cell loss. Thus, the timing of IFN-induced innate responses in acute SIV infection profoundly affects overall disease course and outweighs the detrimental consequences of increased immune activation. Yet, the clinical consequences of manipulation of IFN signalling are difficult to predict in vivo and therapeutic interventions in human studies should be approached with caution.