Impact of Recombinant VSV-HIV Prime, DNA-Boost Vaccine Candidates on Immunogenicity and Viremia on SHIV-Infected Rhesus Macaques.

Currently, no effective vaccine to prevent human immunodeficiency virus (HIV) infection is available, and various platforms are being examined. The vesicular stomatitis virus (VSV) vaccine vehicle can induce robust humoral and cell-mediated immune responses, making it a suitable candidate for the development of an HIV vaccine. Here, we analyze the protective immunological impacts of recombinant VSV vaccine vectors that express chimeric HIV Envelope proteins (Env) in rhesus macaques. To improve the immunogenicity of these VSV-HIV Env vaccine candidates, we generated chimeric Envs containing the transmembrane and cytoplasmic tail of the simian immunodeficiency virus (SIV), which increases surface Env on the particle. Additionally, the Ebola virus glycoprotein was added to the VSV-HIV vaccine particles to divert tropism from CD4 T cells and enhance their replications both in vitro and in vivo. Animals were boosted with DNA constructs that encoded matching antigens. Vaccinated animals developed non-neutralizing antibody responses against both the HIV Env and the Ebola virus glycoprotein (EBOV GP) as well as systemic memory T-cell activation. However, these responses were not associated with observable protection against simian-HIV (SHIV) infection following repeated high-dose intra-rectal SHIV SF162p3 challenges.

Rhesus macaques show increased resistance to repeated SHIV intrarectal exposure following a heterologous regimen of rVSV vector vaccine expressing HIV antigen.

Despite the human immunodeficiency virus (HIV) pandemic continuing worldwide for 40 years, no vaccine to combat the disease has been licenced for use in at risk populations. Here, we describe a novel recombinant vesicular stomatitis virus (rVSV) vector vaccine expressing modified HIV envelope glycoproteins and Ebola virus glycoprotein. Three heterologous immunizations successfully prevented infection by a different clade SHIV in 60% of non-human primates (NHPs). No trend was observed between resistance and antibody interactions. Resistance to infection was associated with high proportions of central memory T-cell CD69 and CD154 marker upregulation, increased IL-2 production, and a reduced IFN-γ response, offering insight into correlates of protection.

Optimal Expression, Function, and Immunogenicity of an HIV-1 Vaccine Derived from the Approved Ebola Vaccine, rVSV-ZEBOV.

Vesicular stomatitis virus (VSV) remains an attractive platform for a potential HIV-1 vaccine but hurdles remain, such as selection of a highly immunogenic HIV-1 Envelope (Env) with a maximal surface expression on recombinant rVSV particles. An HIV-1 Env chimera with the transmembrane domain (TM) and cytoplasmic tail (CT) of SIVMac239 results in high expression on the approved Ebola vaccine, rVSV-ZEBOV, also harboring the Ebola Virus (EBOV) glycoprotein (GP). Codon-optimized (CO) Env chimeras derived from a subtype A primary isolate (A74) are capable of entering a CD4+/CCR5+ cell line, inhibited by HIV-1 neutralizing antibodies PGT121, VRC01, and the drug, Maraviroc. The immunization of mice with the rVSV-ZEBOV carrying the CO A74 Env chimeras results in anti-Env antibody levels as well as neutralizing antibodies 200-fold higher than with the NL4-3 Env-based construct. The novel, functional, and immunogenic chimeras of CO A74 Env with the SIV_Env-TMCT within the rVSV-ZEBOV vaccine are now being tested in non-human primates.

Critical importance of dietary methionine and choline in the maintenance of lung homeostasis during normal and cigarette smoke exposure conditions.

Genetic predispositions and environmental exposures are regarded as the main predictors of respiratory disease development. Although the impact of dietary essential nutrient deficiencies on cardiovascular disease, obesity, and type II diabetes has been widely studied, it remains poorly explored in chronic respiratory diseases. Dietary choline and methionine deficiencies are common in the population, and their impact on pulmonary homeostasis is currently unknown. Mice were fed choline- and/or methionine-deficient diets while being exposed to room-air or cigarette smoke for up to 4 wk. Lung functions were assessed using the FlexiVent. Pulmonary transcriptional activity was assessed using gene expression microarrays and quantitative PCR. Immune cells, cytokines, and phosphatidylcholine were quantified in the bronchoalveolar lavage. In this study, we found that short-term dietary choline and/or methionine deficiencies significantly affect lung function in mice in a reversible manner. It also reduced transcriptional levels of collagens and elastin as well as pulmonary surfactant phosphatidylcholine levels. We also found that dietary choline and/or methionine deficiencies markedly interfered with the pulmonary response to cigarette smoke exposure, modulating lung function and dampening inflammation. These findings clearly show that dietary choline and/or methionine deficiencies can have dramatic pathophysiological effects on the lungs and can also affect the pathobiology of cigarette smoke-induced pulmonary alterations. Expanding our knowledge in the field of "nutri-respiratory research" may reveal a crucial role for essential nutrients in pulmonary health and disease, which may prove to be as relevant as genetic predispositions and environmental exposures.