The anti-caspase inhibitor Q-VD-OPH prevents AIDS disease progression in SIV-infected rhesus macaques

Apoptosis has been proposed as a key mechanism responsible for CD4+ T cell depletion and immune dysfunction during HIV infection. We demonstrated that Q-VD-OPH, a caspase inhibitor, inhibits spontaneous and activation-induced death of T cells from SIV-infected rhesus macaques (RMs). When administered during the acute phase of infection, Q-VD-OPH was associated with (a) reduced levels of T cell death, (b) preservation of CD4+/CD8+ T cell ratio in lymphoid organs and in the gut, (c) maintenance of memory CD4+ T cells, and (d) increased specific CD4+ T cell response associated with the expression of cytotoxic molecules. Although therapy was limited to the acute phase of infection, Q-VD-OPH-treated RMs showed lower levels of both viral load and cell-associated SIV DNA as compared with control SIV-infected RMs throughout the chronic phase of infection, and prevented the development of AIDS. Overall, our data demonstrate that Q-VD-OPH injection in SIV-infected RMs may represent an adjunctive therapeutic agent to control HIV infection and delaying disease progression to AIDS.This article is dedicated to the memory of Bruno Hurtrel. We also thank Jean-Claude Ameisen for his initial support. We acknowledge Celine Gommet (Institut Pasteur) for her expertise in the follow-up of our primate cohort. We also acknowledge Francois Villinger, who performed TRIM5a polymorphism. ML and JG were supported by fellowships from ANRS. RS thanks Fundacao para a Ciencia e a Tecnologia (FCT) for Investigator FCT Grant IF/00021/2014. This study was supported by research funding from ANRS and CIHR (MOP-133476) to JE. VR is supported by a fellowship from FCT (code SFRH/BD/64064/2009). JE thanks the Canada Research Chair program for financial assistance

Extremely low viral reservoir in treated chronically HIV-1-infected individuals

Altres ajuts: This research was sponsored in part by Grifols and by Merck Sharp & Dohme España, S.A. (IISP 54925). The funding organizations had no input in the design of the study; in the collection, analyses, or interpretation of the data; writing of the manuscript; or in the decision to submit the study for publication. NH received a post-doctoral grant from the Jaqueline Beytout Foundation. FG received the support of "José María Segovia de Arana" contracts (2019) and MMT from the NIH (R01AI143457).Small viral reservoirs are found predominantly in HIV-1 controllers and individuals treated during acute/early HIV-1 infection. However, other HIV + individuals could naturally also harbour low viral reservoirs. We screened 451 HIV-1-infected treated-individuals with suppressed plasma viremia for at least 3 years and stored cryopreserved peripheral blood mononuclear cells (PBMCs). Total HIV-DNA was analysed in PBMCs with ddPCR. Individuals with 50 HIV-DNA copies/10 6 PBMCs) to analyse total HIV-DNA, T-cell and NK-cell populations, HIV-1 specific antibodies, and plasma inflammation markers. We found that 9.3% of the individuals screened had <50 HIV-DNA copies/10 6 PBMCs. At least 66% initiated cART during the chronic phase of HIV-1 infection (cp-LoViReT). Cp-LoViReT harboured lower levels of HIV-DNA before cART and after treatment introduction the decays were greater compared to controls. They displayed a marked decline in quantity and avidity in HIV-specific antibodies after initiation of cART. Cp-LoViReT had fewer CD8 + T and T in the absence of cART, and higher CD8 + T after 18 months on therapy. Treated chronically HIV-1-infected LoViReT represent a new phenotype of individuals characterized by an intrinsically reduced viral reservoir, less impaired CD8 + T-cell compartment before cART, and low circulating HIV-1 antigens despite being treated in the chronic phase of infection. The identification of this unique group of individuals is of great interest for the design of future eradication studies. MSD Spai

Affinity for the Interface Underpins Potency of Antibodies Operating In Membrane Environments

The contribution of membrane interfacial interactions to recognition of membrane-embedded antigens by antibodies is currently unclear. This report demonstrates the optimization of this type of antibodies via chemical modification of regions near the membrane but not directly involved in the recognition of the epitope. Using the HIV-1 antibody 10E8 as a model, linear and polycyclic synthetic aromatic compounds are introduced at selected sites. Molecular dynamics simulations predict the favorable interactions of these synthetic compounds with the viral lipid membrane, where the epitope of the HIV-1 glycoprotein Env is located. Chemical modification of 10E8 with aromatic acetamides facilitates the productive and specific recognition of the native antigen, partially buried in the crowded environment of the viral membrane, resulting in a dramatic increase of its capacity to block viral infection. These observations support the harnessing of interfacial affinity through site-selective chemical modification to optimize the function of antibodies that target membrane-proximal epitopes.We are grateful to Professor Ueda (Kyushu University) for valuable advice. C.D. acknowledges RES (Red Espanola de Supercomputacio ' n) for providing computational resources. S.I. received a pre-doctoral fellowship from the Basque Government. P.C. acknowledges a research associate contract from the University of the Basque Country (DOCREC18/01) and a postdoctoral fellowship from the Basque Government (POS_2018_1_0066).This study was supported by the following grants: European Commission (790012 SI H2020MSCA-IF-2017 to E.R., J.-P.J., and J.L.N.); US NIAID (NIH) (R01 AI143563 to M.B.Z.); James B. Pendleton Charitable Trust (to M.B.Z.); Grant-in-Aid for Scientific Research on Innovative Areas "Chemistry for Multimolecular Crowding Biosystems, JSPS KAKENHI (JP17H06349 to A.O.); JSPS KAKENHI (15K06962 and 20H03228 to J.M.M.C.); Spanish MINECO (BIO2015-64421R and MINECO/AEI/FEDER, UE to J.L.N.); Spanish MCIU (RTI2018-095624B-C21 and MCIU/AEI/FEDER, UE to J.L.N.); and the Basque Government (IT1196-19) (to J.L.N.). C.E. acknowledges funding from Medical Research Council (MC_UU_12010/unit programs G0902418 and MC_UU_12025), Wolfson Foundation, Deutsche Forschungsgemeinschaft (Research unit 1905, Excellence Cluster Balance of the Microverse, Collaborative Research Centre 1278 Polytarget), Wellcome Institutional Strategic Support Fund, Oxford internal funds (EPA Cephalosporin Fund and John Fell Fund), and support from the Micron Oxford Advanced Bioimaging Unit (Wellcome Trust funding 107457/Z/15/Z). This research was undertaken, in part, thanks to funding from the CIFAR Azrieli Global Scholar program (to J.-P.J.) and the Canada Research Chairs program (950-231604 to J.-P.J.). This work was also supported by the Platform Project for Supporting Drug Discovery and Life Science Research (Basis for Supporting Innovative Drug Discovery and Life Science Research [BINDS] from AMED JP19am0101091)

HIV/SIV Infection Primes Monocytes and Dendritic Cells for Apoptosis

Subversion or exacerbation of antigen-presenting cells (APC) death modulates host/pathogen equilibrium. We demonstrated during in vitro differentiation of monocyte-derived macrophages and monocyte-derived dendritic cells (DCs) that HIV sensitizes the cells to undergo apoptosis in response to TRAIL and FasL, respectively. In addition, we found that HIV-1 increased the levels of pro-apoptotic Bax and Bak molecules and decreased the levels of anti-apoptotic Mcl-1 and FLIP proteins. To assess the relevance of these observations in the context of an experimental model of HIV infection, we investigated the death of APC during pathogenic SIV-infection in rhesus macaques (RMs). We demonstrated increased apoptosis, during the acute phase, of both peripheral blood DCs and monocytes (CD14+) from SIV+RMs, associated with a dysregulation in the balance of pro- and anti-apoptotic molecules. Caspase-inhibitor and death receptors antagonists prevented apoptosis of APCs from SIV+RMs. Furthermore, increased levels of FasL in the sera of pathogenic SIV+RMs were detected, compared to non-pathogenic SIV infection of African green monkey. We suggest that inappropriate apoptosis of antigen-presenting cells may contribute to dysregulation of cellular immunity early in the process of HIV/SIV infection

Increased neutrophil apoptosis in chronically SIV-infected macaques

Abstract Polymorphonuclear neutrophils (PMN) from chronically HIV-infected individuals have been reported to be more prone to die. However, although non-human primates models have been extensively used for improving our knowledge on T cell immunity, the impact of SIV-infection on PMN, in relationships with disease severity, has never been assessed. In our study, we demonstrate that PMN from Rhesus macaques (RMs) of Chinese origin chronically infected with the virulent strain SIVmac251 display increased susceptibility to undergo apoptosis as compared to PMN from RMs infected with the non-pathogenic SIVΔnef strain. PMN apoptosis was significantly increased in RMs progressing faster to AIDS as compared to non-progressors RMs. Furthermore, the percentage of apoptotic cells correlated with PMN activation state reflected by increased CD11b expression and reactive oxygen species production. Interestingly, whereas inflammatory cytokines IL-8 and IL-1β prevent in vitro PMN death, the levels of those cytokines were low in RMs progressing towards AIDS. Altogether, increased PMN death during SIV infection is a new pathogenic effect associated with AIDS progression, adding to the long list of markers associated with disruption of defense against infection.</p

Simian Immunodeficiency Virus Promoter Exchange Results in a Highly Attenuated Strain That Protects against Uncloned Challenge Virus

Among the many simian immunodeficiency virus (SIV) immunogens, only live attenuated viral vaccines have afforded strong protection to a natural pathogenic isolate. Since the promoter is crucial to the tempo of viral replication in general, it was reasoned that promoter exchange might confer a novel means of attenuating SIV. The core enhancer and promoter sequences of the SIV macaque 239nefstop strain (NF-κB/Sp1 region from −114 bp to mRNA start) have been exchanged for those of the human cytomegalovirus immediate-early promoter (CMV-IE; from −525 bp to mRNA start). During culture of the resulting virus, referred to as SIVmegalo, on CEMx174 or rhesus macaque peripheral blood mononuclear cells, deletions arose in distal regions of the CMV-IE sequences that stabilized after 1 or 2 months of culture. However, when the undeleted form of SIVmegalo was inoculated into rhesus macaques, animals showed highly controlled viremia during primary and persistent infection. Compared to parental virus infection in macaques, primary viremia was reduced by >1,000-fold to undetectable levels, with little sign of an increase of cycling cells in lymph nodes, CD4(+) depletion, or altered T-cell activation markers in peripheral blood. Moreover, in contrast to wild-type infection in most infected animals, the nef stop mutation did not revert to the wild-type codon, indicating yet again that replication was dramatically curtailed. Despite such drastic attenuation, antibody titers and enzyme-linked immunospot reactivity to SIV peptides, although slower to appear, were comparable to those seen in a parental virus infection. When animals were challenged intravenously at 4 or 6 months with the uncloned pathogenic SIVmac251 strain, viremia was curtailed by ∼1,000-fold at peak height without any sign of hyperactivation in CD4(+)- or CD8(+)-T-cell compartment or increase in lymph node cell cycling. To date, there has been a general inverse correlation between attenuation and protection; however, these findings show that promoter exchange constitutes a novel means to highly attenuate SIV while retaining the capacity to protect against challenge virus

Nonpathogenesis of Simian Immunodeficiency Virus Infection Is Associated with Reduced Inflammation and Recruitment of Plasmacytoid Dendritic Cells to Lymph Nodes, Not to Lack of an Interferon Type I Response, during the Acute Phase▿

Divergent Toll-like receptor 7 (TLR7) and TLR9 signaling has been proposed to distinguish pathogenic from nonpathogenic simian immunodeficiency virus infection in primate models. We demonstrate here that increased expression of type I interferon in pathogenic rhesus macaques compared to nonpathogenic African green monkeys was associated with the recruitment of plasmacytoid dendritic cells in the lymph nodes and the presence of an inflammatory environment early after infection, instead of a difference in the TLR7/9 response