HIV gag ANTIGEN SPECIFIC T-HELPER AND GRANULE-DEPENDENT CD8 T CELL ACTIVITY IN EXPOSED BUT UNINFECTED HETEROSEXUAL PARTNERS OF HIV-1 INFECTED INDIVIDUALS IN NORTH INDIA

Department of Internal Medicine, Post Graduate Institute of Medical Education and Research, Chandigarh, India; Department of Biochemistry, Panjab University, Chandigarh, India; Department of Medical Microbiology, Post Graduate Institute of Medical Education and Research, Chandigarh, India

^* To whom correspondence should be addressed. Email: awanchu{at}yahoo.com.

	Abstract

Repeated exposure to human immunodeficiency virus (HIV) does not always result in HIV infection and several cohorts of HIV exposed but uninfected (EU) individuals have been described. We studied T helper and granule-dependent CTL activity in a group of thirty EU partners of HIV-1 infected individuals. HIV-1 specific helper T cell activity was studied by measuring the levels of interleukin (IL)-2 produced by peripheral blood mononuclear cells (PBMCs) and the granule- dependent cytotoxic T lymphocyte (CTL) activity by measuring the intracellular perforin and granzyme B expression in CD8+ T cells after stimulation with gag p24 antigen. Elevated IL-2 production by PBMCs after p24 stimulation occurred in EU individuals. Perforin and granzyme B expression in CD8+ T cells also was higher among EU individuals than healthy controls. HIV specific helper T cell and granule-dependent CTL activity inversely correlated with time since last unprotected sexual exposure in these individuals. In our cohort, activation of T helper and granule-dependent CTL activity against HIV might be due to unprotected sexual contact. These results indicate that HIV-1 specific T cell responses could play a role in protection against acquiring infection in this cohort of EU individuals.