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Open Access Short report

Increased cellular immune responses and CD4+ T-cell proliferation correlate with reduced plasma viral load in SIV challenged recombinant simian varicella virus - simian immunodeficiency virus (rSVV-SIV) vaccinated rhesus macaques

Bapi Pahar1, Wayne L Gray2, Kimberly Phelps3, Elizabeth S Didier4, Eileen deHaro4, Preston A Marx4 and Vicki L Traina-Dorge45*

Author Affiliations

1 Division of Comparative Pathology, Tulane National Primate Research Center, Tulane University School of Medicine, Covington, LA, USA

2 University of Arkansas for Medical Sciences, Little Rock, AR, USA

3 Departments of Chemistry and Physics, College of Sciences, Louisiana State University Shreveport, Shreveport, LA, USA

4 Division of Microbiology, Tulane National Primate Research Center, Tulane University School of Medicine, Covington, LA USA

5 Division of Microbiology, Tulane National Primate Research Center, 18703 Three Rivers Road, Covington, LA 70433, USA

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Virology Journal 2012, 9:160  doi:10.1186/1743-422X-9-160

Published: 13 August 2012

Abstract

Background

An effective AIDS vaccine remains one of the highest priorities in HIV-research. Our recent study showed that vaccination of rhesus macaques with recombinant simian varicella virus (rSVV) vector – simian immunodeficiency virus (SIV) envelope and gag genes, induced neutralizing antibodies and cellular immune responses to SIV and also significantly reduced plasma viral loads following intravenous pathogenic challenge with SIVMAC251/CX1.

Findings

The purpose of this study was to define cellular immunological correlates of protection in rSVV-SIV vaccinated and SIV challenged animals. Immunofluorescent staining and multifunctional assessment of SIV-specific T-cell responses were evaluated in both Experimental and Control vaccinated animal groups. Significant increases in the proliferating CD4+ T-cell population and polyfunctional T-cell responses were observed in all Experimental-vaccinated animals compared with the Control-vaccinated animals.

Conclusions

Increased CD4+ T-cell proliferation was significantly and inversely correlated with plasma viral load. Increased SIV-specific polyfunctional cytokine responses and increased proliferation of CD4+ T-cell may be crucial to control plasma viral loads in vaccinated and SIVMAC251/CX1 challenged macaques.

Keywords:
Simian varicella virus (SVV); Simian immunodeficiency virus (SIV); T-cells; Cytokine; Memory; Proliferation; Vaccine