Characterization of SIV-specific CD4+ T-helper proliferative responses in macaques immunized with live-attenuated SIV.
Analysis of immune responses generated by live-attenuated simian immunodeficiency virus (SIV) strains may provide clues to the mechanisms of protective immunity induced by this approach. We examined SIV-specific T-helper responses in macaques immunized with the live-attenuated SIV strains SIVmac239deltanef and SIVmac239delta3. Optimization of the concentration and duration of antigenic stimulation resulted in the detection of relatively strong SIV-specific proliferative responses, with peak stimulation indices of up to 84. SIV-specific proliferative responses were mediated by CD4+ T cells and were major histocompatibility (MHC) class II restricted. Limiting dilution analysis revealed SIV-specific T-helper precursor frequencies of up to 96 per 10(6) peripheral blood mononuclear cells (PBMC). Intracellular flow-cytometric analysis demonstrated the production of interleukin (IL)-2, interferon (IFN)-gamma, RANTES and macrophage inhibitory protein-1alpha (MIP-1alpha) by T lymphocytes from SIVmac239deltanef-vaccinated animals following SIV p55 stimulation. Induction of strong SIV-specific T-helper responses by live-attenuated SIV vaccines may play a role in their ability to induce protective immunity.
Gauduin
M C
MC
Division of Immunology, New England Regional Primate Research Center, Harvard Medical School, Southborough, MA 01772-9102, USA.
Glickman
R L
RL
Ahmad
S
S
Yilma
T
T
Johnson
R P
RP
D016915:AIDS Vaccines / Q000276:immunology*; D000818:Animals; D018791:CD4 Lymphocyte Count; D005434:Flow Cytometry; D007111:Immunity, Cellular / Q000276:immunology; D007114:Immunization / Q000662:veterinary; D007371:Interferon-gamma / Q000276:immunology; D007376:Interleukin-2 / Q000276:immunology; D008213:Lymphocyte Activation; D008253:Macaca mulatta; D016097:Simian Acquired Immunodeficiency Syndrome / Q000276:immunology / Q000517:prevention & control; D015302:Simian Immunodeficiency Virus / Q000276:immunology*; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*; D014613:Vaccines, Attenuated / Q000276:immunology
D016915:AIDS Vaccines; D007376:Interleukin-2; D014613:Vaccines, Attenuated; D007371:Interferon-gamma