UMMS Affiliation

Department of Medicine, Division of Preventive and Behavioral Medicine

Date

1-23-2009

Document Type

Article

Subjects

Animals; Antibodies, Viral; CD4-Positive T-Lymphocytes; CD8-Positive T-Lymphocytes; Immunization; Macaca mulatta; RNA, Viral; Simian Acquired Immunodeficiency Syndrome; Simian immunodeficiency virus; Vesiculovirus; Viral Load

Disciplines

Immunology and Infectious Disease | Immunopathology

Abstract

Strains of simian immunodeficiency virus (SIV) that are limited to a single cycle of infection were evaluated for the ability to elicit protective immunity against wild-type SIV(mac)239 infection of rhesus macaques by two different vaccine regimens. Six animals were inoculated at 8-week intervals with 6 identical doses consisting of a mixture of three different envelope variants of single-cycle SIV (scSIV). Six additional animals were primed with a mixture of cytoplasmic domain-truncated envelope variants of scSIV and boosted with two doses of vesicular stomatitis virus glycoprotein (VSV G) trans-complemented scSIV. While both regimens elicited detectable virus-specific T cell responses, SIV-specific T cell frequencies were more than 10-fold higher after boosting with VSV G trans-complemented scSIV (VSV G scSIV). Broad T cell recognition of multiple viral antigens and Gag-specific CD4(+) T cell responses were also observed after boosting with VSV G scSIV. With the exception of a single animal in the repeated immunization group, all of the animals became infected following an intravenous challenge with SIV(mac)239. However, significantly lower viral loads and higher memory CD4(+) T cell counts were observed in both immunized groups relative to an unvaccinated control group. Indeed, both scSIV immunization regimens resulted in containment of SIV(mac)239 replication after challenge that was as good as, if not better than, what has been achieved by other non-persisting vaccine vectors that have been evaluated in this challenge model. Nevertheless, the extent of protection afforded by scSIV was not as good as typically conferred by persistent infection with live, attenuated SIV. These observations have potentially important implications to the design of an effective AIDS vaccine, since they suggest that ongoing stimulation of virus-specific immune responses may be essential to achieving the degree of protection afforded by live, attenuated SIV.

Rights and Permissions

Citation: Jia B, Ng SK, DeGottardi MQ, Piatak M Jr, Yuste E, et al. (2009) Immunization with Single-Cycle SIV Significantly Reduces Viral Loads After an Intravenous Challenge with SIVmac239. PLoS Pathog 5(1): e1000272. doi:10.1371/journal.ppat.1000272 Link to article on publisher's site

Comments

Copyright 2009 Jia et al. 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.

Related Resources

Link to Article in PubMed

Keywords

Antibodies, Enzyme-linked immunoassays, Immune response, Memory T cells, SIV, T cells, Viral load, Viral replication

PubMed ID

19165322

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