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Session 45 Poster Session Exposed Uninfected Individuals Session Time: 4:30-6:30 pm Room 4E-F

259-T. HIV-1-Specific T-Lymphocyte Responses Are Detectable in a Population of HIV-Negative African Men with Urethritis S. Galvin*1, L. Garba1, S. Gama2, D. Namakwa2, M. Cohen1, and J. Frelinger1 1Univ. of North Carolina, Chapel Hill and 2UNC Project, Lilongwe, Malawi Background: HIV-specific T-lymphocyte responses, especially CD8+ lymphocytes, have been found in small, select groups of highly exposed seronegative persons. To determine whether these responses were detectable in a general African high-risk population with more variable exposure, we performed a study looking for HIV-specific CD4+ and CD8+ lymphocyte responses in a group of HIV-negative men presenting with urethritis to an urban STD clinic in Lilongwe, Malawi. Methods: The subjects were male patients presenting with symptoms of urethritis to the STD clinic in Lilongwe Central Hospital. Each subject's whole blood was stimulated with pools of HIV env, pol, or gag peptides using a modified Becton Dickinson intracellular cytokine staining protocol. Each subject had one negative control with no peptide and one positive control stimulated with PMA and ionomycin. After stimulation, the samples were frozen at -70 and sent to the USA for permeabilization and staining with CD3, CD4 or CD8, CD69, and IFN-gamma antibodies and flow cytometry analysis. Samples were included in the final analysis if they had sufficient events (>10,000) and considered positive if the HIV peptide exposed pool had more CD4 or CD8 lymphocytes staining for both CD69 and IFN-gamma than the negative control. A chi2 test with Yates correction was performed to determine if the proportion of positive events in the stimulated sample was significantly more than the control sample in order to label a sample as positive. Results: 41 HIV-negative subjects had samples adequate for analysis. Of these, 8 (19.5%) had significant HIV-specific T-lymphocyte responses. 3 had both CD4 and CD8 responses, 3 had only CD4 responses, and 2 had only CD8 responses. 14 HIV-positive subjects were tested. 9 of the 14 (64%) had HIV-specific responses. 11 HIV-negative Malawian controls without STDs were also analyzed and one responder was found. In contrast to the HIV-positive persons, trends for high-risk seronegative responders were less positive pools per patient, more CD4 responses, and more env responses. Conclusions: HIV-specific responses are detectable in 19.5% of HIV-negative persons in a high-risk population of African men.

©2002 9th Conference on Retroviruses and Opportunistic Infections