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The article discusses a study which examined the protective efficacy of several Zika virus (ZIKV) vaccine candidates in rhesus monkeys. The study investigated the effect of the DNA-M-Env vaccine on antibody responses made by enzyme-linked immunosorbent assay (ELISA). It revealed the effectiveness an adenovirus vector-based vaccine and a purified inactivated virus vaccine against ZIKV in rhesus monkeys.

The article discusses a study related to exploration of single Broadly neutralizing antibodies (bNAbs) selection for resistant simian-HIV (SHIV) variants in prophylactic and therapeutic experiments in rhesus monkeys. It mentions single bNAbs efficiently select resistant viruses for establishing infection and demonstrating importance of bNAb cocktails for HIV-1 prevention and V3 glycan-dependent antibody PGT121 alone failing to protect against a mixed challenge with SHIV-SF162P3 and SHIV-325c.

Zika virus (ZIKV) is responsible for a major ongoing epidemic in the Americas and has been causally associated with fetal microcephaly. The development of a safe and effective ZIKV vaccine is therefore an urgent global health priority. Here we demonstrate that three different vaccine platforms protect against ZIKV challenge in rhesus monkeys. A purified inactivated virus vaccine induced ZIKV-specific neutralizing antibodies and completely protected monkeys against ZIKV strains from both Brazil and Puerto Rico. Purified immunoglobulin from vaccinated monkeys also conferred passive protection in adoptive transfer studies. A plasmid DNA vaccine and a single-shot recombinant rhesus adenovirus serotype 52 vector vaccine, both expressing ZIKV premembrane and envelope, also elicited neutralizing antibodies and completely protected monkeys against ZIKV challenge. These data support the rapid clinical development of ZIKV vaccines for humans. [ABSTRACT FROM AUTHOR]

Preclinical studies of viral vector--based HIV-1 vaccine candidates have previously shown partial protection against neutralization-resistant virus challenges in rhesus monkeys. In this study, we evaluated the protective efficacy of adenovirus serotype 26 (Ad26) vector priming followed by purified envelope (Env) glycoprotein boosting. Rhesus monkeys primed with Ad26 vectors expressing SIVsmE543 Env, Gag, and Pol and boosted with AS01B-adjuvanted SIVmac32H Env gp140 demonstrated complete protection in 50% of vaccinated animals against a series of repeated, heterologous, intrarectal SIVmac251 challenges that infected all controls. Protective efficacy correlated with the functionality of Env-specific antibody responses. Comparable protection was also observed with a similar Ad/Env vaccine against repeated, heterologous, intrarectal SHIV-SF162P3 challenges. These data demonstrate robust protection by Ad/Env vaccines against acquisition of neutralization-resistant virus challenges in rhesus monkeys. [ABSTRACT FROM AUTHOR]

CD4 T cells promote innate and adaptive immune responses, but how vaccine-elicited CD4 T cells contribute to immune protection remains unclear. We evaluated whether induction of virus-specific CD4 T cells by vaccination would protect mice against infection with chronic lymphocytic choriomeningitis virus (LCMV). Immunization with vaccines that selectively induced CD4 T cell responses resulted in catastrophic inflammation and mortality after challenge with a persistent strain of LCMV. Immunopathology required antigen-specific CD4 T cells and was associated with a cytokine storm, generalized inflammation, and multi-organ system failure. Virus-specific CD8 T cells or antibodies abrogated the pathology. These data demonstrate that vaccine-elicited CD4 T cells in the absence of effective antiviral immune responses can trigger lethal immunopathology. [ABSTRACT FROM AUTHOR]

Sustained virologic control of human immunodeficiency virus type 1 (HIV-1) infection after discontinuation of antiretroviral therapy (ART) is a major goal of the HIV-1 cure field. A recent study reported that administration of an antibody against α 4 β 7 induced durable virologic control after ART discontinuation in 100% of rhesus macaques infected with an attenuated strain of simian immunodeficiency virus (SIV) containing a stop codon in nef We performed similar studies in 50 rhesus macaques infected with wild-type, pathogenic SIVmac251. In animals that initiated ART during either acute or chronic infection, anti-α 4 β 7 antibody infusion had no detectable effect on the viral reservoir or viral rebound after ART discontinuation. These data demonstrate that anti-α 4 β 7 antibody administration did not provide therapeutic efficacy in the model of pathogenic SIVmac251 infection of rhesus macaques., (Copyright © 2019 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

Adenovirus serotype 5 (Ad5) vaccine vectors elicit robust CD8 + T cell responses, but these responses typically exhibit a partially exhausted phenotype. However, the immunologic mechanism by which Ad5 vectors induce dysfunctional CD8 + T cells has not previously been elucidated. Here we demonstrate that, following immunization of B6 mice, Ad5 vectors elicit antigen-specific IL-10 + CD4 + T cells with a distinct transcriptional profile in a dose-dependent fashion. In rhesus monkeys, we similarly observed upregulated expression of IL-10 and PD-1 by CD4 + T cells following Ad5 vaccination. These cells markedly suppressed vaccine-elicited CD8 + T cell responses in vivo and IL-10 blockade increased the frequency and functionality of antigen-specific CD8 + T cells as well as improved protective efficacy against challenge with recombinant Listeria monocytogenes . Moreover, induction of these inhibitory IL-10 + CD4 + T cells correlated with IL-27 expression and IL-27 blockade substantially improved CD4 + T cell functionality. These data highlight a role for IL-27 in the induction of inhibitory IL-10 + CD4 + T cells, which suppress CD8 + T cell magnitude and function following Ad5 vector immunization. A deeper understanding of the cytokine networks and transcriptional profiles induced by vaccine vectors should lead to strategies to improve the immunogenicity and protective efficacy of viral vector-based vaccines., Competing Interests: Competing interests: The authors declare that they have no competing interests.