Fitness Ranking of Individual Mutants Drives Patterns of Epistatic Interactions in HIV-1

This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

Peptides Derived from HIV-1 Integrase that Bind Rev Stimulate Viral Genome Integration

The human immunodeficiency virus type 1 (HIV-1) integrase protein (IN), catalyzes the integration of viral DNA into the host cell genome. IN catalyzes the first step of the integration process, namely the 3′-end processing in which IN removes a pGT dinucleotide from the 3′ end of each viral long terminal repeat (LTR). Following nuclear import of the viral preintegration complex, the host chromosomal DNA becomes accessible to the viral cDNA and the second step of the integration process, namely the strand-transfer step takes place. This ordered sequence of events, centered on integration, is mandatory for HIV replication. assay system, we show that INr-1 and INr-2 are able to abrogate the inhibitory effects exerted by Rev and Rev-derived peptides on integrase activity. Both INr-1 and INr-2 were found to be cell-permeable and nontoxic, allowing a study of their effect in HIV-1-infected cultured cells. Interestingly, both INr peptides stimulated virus infectivity as estimated by production of the viral P24 protein, as well as by determination of the appearance of newly formed virus particles. Furthermore, kinetics studies revealed that the cell-permeable INr peptides enhance the integration process, as was indeed confirmed by direct determination of viral DNA integration by real-time PCR.The results of the present study raise the possibility that in HIV-infected cells, the Rev protein may be involved in the integration of proviral DNA by controlling/regulating the activity of the integrase. Release from such inhibition leads to stimulation of IN activity and multiple viral DNA integration events

Mesenchymal Stem Cells Induce T-Cell Tolerance and Protect the Preterm Brain after Global Hypoxia-Ischemia

Hypoxic-ischemic encephalopathy (HIE) in preterm infants is a severe disease for which no curative treatment is available. Cerebral inflammation and invasion of activated peripheral immune cells have been shown to play a pivotal role in the etiology of white matter injury, which is the clinical hallmark of HIE in preterm infants. The objective of this study was to assess the neuroprotective and anti-inflammatory effects of intravenously delivered mesenchymal stem cells (MSC) in an ovine model of HIE. In this translational animal model, global hypoxia-ischemia (HI) was induced in instrumented preterm sheep by transient umbilical cord occlusion, which closely mimics the clinical insult. Intravenous administration of 2 x 106MSC/kg reduced microglial proliferation, diminished loss of oligodendrocytes and reduced demyelination, as determined by histology and Diffusion Tensor Imaging (DTI), in the preterm brain after global HI. These anti-inflammatory and neuroprotective effects of MSC were paralleled by reduced electrographic seizure activity in the ischemic preterm brain. Furthermore, we showed that MSC induced persistent peripheral T-cell tolerance in vivo and reduced invasion of T-cells into the preterm brain following global HI. These findings show in a preclinical animal model that intravenously administered MSC reduced cerebral inflammation, protected against white matter injury and established functional improvement in the preterm brain following global HI. Moreover, we provide evidence that induction of T-cell tolerance by MSC might play an important role in the neuroprotective effects of MSC in HIE. This is the first study to describe a marked neuroprotective effect of MSC in a translational animal model of HIE

Uterine Epithelial Cell Regulation of DC-SIGN Expression Inhibits Transmitted/Founder HIV-1 Trans Infection by Immature Dendritic Cells

Sexual transmission accounts for the majority of HIV-1 infections. In over 75% of cases, infection is initiated by a single variant (transmitted/founder virus). However, the determinants of virus selection during transmission are unknown. Host cell-cell interactions in the mucosa may be critical in regulating susceptibility to infection. We hypothesized in this study that specific immune modulators secreted by uterine epithelial cells modulate susceptibility of dendritic cells (DC) to infection with HIV-1.Here we report that uterine epithelial cell secretions (i.e. conditioned medium, CM) decreased DC-SIGN expression on immature dendritic cells via a transforming growth factor beta (TGF-β) mechanism. Further, CM inhibited dendritic cell-mediated trans infection of HIV-1 expressing envelope proteins of prototypic reference. Similarly, CM inhibited trans infection of HIV-1 constructs expressing envelopes of transmitted/founder viruses, variants that are selected during sexual transmission. In contrast, whereas recombinant TGF- β1 inhibited trans infection of prototypic reference HIV-1 by dendritic cells, TGF-β1 had a minimal effect on trans infection of transmitted/founder variants irrespective of the reporter system used to measure trans infection.Our results provide the first direct evidence for uterine epithelial cell regulation of dendritic cell transmission of infection with reference and transmitted/founder HIV-1 variants. These findings have immediate implications for designing strategies to prevent sexual transmission of HIV-1

Cellular immune responses during high-dose interferon-alpha induction therapy for hepatitis C virus infection.

BACKGROUND: The effect that high-dose interferon (IFN)-alpha induction therapy for hepatitis C virus (HCV) infection has on cellular immune responses is currently unknown. METHODS: Thirty-one treatment-naive patients with chronic HCV infection received amantadine and ribavirin, combined with 6 weeks of high-dose IFN-alpha-2b induction therapy followed by weekly pegylated IFN-alpha-2b, for 24 or 48 weeks. Using IFN-gamma and interleukin (IL)-2 enzyme-linked immunospot (ELISpot) assays, we analyzed the pattern of cytokine secretion by structural and nonstructural HCV- and cytomegalovirus (CMV)-specific T cells before, during, and after therapy. RESULTS: HCV-specific T cell responses, which were predominantly IFN-gamma secreting and which correlated with alanine transaminase levels (r2 = 0.45; P = .001), were found before treatment in 10 of 15 patients with a sustained virological response (SVR) and in 11 of 16 in the non-SVR group. There was a striking loss of IFN-gamma and IL-2 HCV-specific T cells during therapy, predominantly in the SVR group. This response recovered after cessation of therapy, regardless of outcome. Suppression of CMV-specific T cell responses, in addition to total lymphocyte counts, was also observed. CONCLUSIONS: High-dose IFN-alpha induction therapy leads to a profound decline in IL-2- and IFN-gamma-secreting HCV- and CMV-specific T cells. These data indicate that restoration of T cell responses is unlikely to be causally linked to an early response or SVR to therapy

Hepatitis B virus incidence and risk factors among Human Immunodeficiency Virus-1 negative men who have sex with men in Kenya.

No data exist on hepatitis B virus (HBV) incidence among African men who have sex with men (MSM). We tested plasma samples archived between 2005 and 2014 for HBV core antibody or surface antigen seroconversion in a cohort of 312 initially human immunodeficiency virus (HIV)-1-negative MSM with no evidence of prior HBV infection. Hepatitis B virus incidence was 6.0/100 person-years (95% confidence interval [CI], 3.9-9.1). Hepatitis B virus acquisition was associated with being uncircumcised (adjusted incidence rate ratio [aIRR], 5.0; 95% CI, 1.5-16.8), recent HIV-1 acquisition (aIRR, 2.9; 95% CI, 1.1-7.7), rape (aIRR, 5.0; 95% CI, 1.2-20.4), and any tertiary education (aIRR, 3.2; 95% CI, 1.1-9.7). African MSM have a substantial risk of HBV acquisition and require vaccination urgently

Hepatitis B virus incidence and risk factors among human immunodeficiency virus-1 negative men who have sex with men in Kenya

No data exist on hepatitis B virus (HBV) incidence among African men who have sex with men (MSM). We tested plasma samples archived between 2005 and 2014 for HBV core antibody or surface antigen seroconversion in a cohort of 312 initially human immunodeficiency virus (HIV)-1-negative MSM with no evidence of prior HBV infection. Hepatitis B virus incidence was 6.0/100 person- years (95% confidence interval [CI], 3.9-9.1). Hepatitis B virus acquisition was associated with being uncircumcised (adjusted incidence rate ratio [aIRR], 5.0; 95% CI, 1.5-16.8), recent HIV-1 acquisition (aIRR, 2.9; 95% CI, 1.1-7.7), rape (aIRR, 5.0; 95% CI, 1.2-20.4), and any tertiary education (aIRR, 3.2; 95% CI, 1.1-9.7). African MSM have a substantial risk of HBV acquisition and require vaccination urgently