Petros Beyene (PhD)Kassu Afework2018-07-132023-11-082018-07-132023-11-082001-06http://etd.aau.edu.et/handle/123456789/8467The present study assessed whether expansion of a specific sub-population of CD8+ T cells is responsible for variations in CD8+ T cell counts; and also investigated the effect of incident intestinal parasitic infection and treatment on the profile of various differentiation and activation markers on CD4+ and CD8+ T cells from HIV-1 infected and uninfected adult Ethiopians (n=150). The pattern of CD8+ T cell population in whole blood samples of 86 subjects (60 HIV negative and 26 HIY positive) from Akaki and Wonji were analysed. The effect of incident intestinal parasites and their treatment was studied on cryo preserved PBMCs of 64 subjects (41 HIY- and 23 HIV+). In both cases, the samples were stained with antibodies to various T cell differentiation and activation markers and naiVe, memory, effector, memory/effector, activated and resting CD4+ and CD8+ T cell subsets were quantified by triple colour FACScan. Significantly higher (P<O.05) count of CD8+ T cells in Akaki HIV negative subjects was reflected in a proportional increase in each of the CD8+ T cell compattment studied. Incident intestinal parasitic infections resulted in a significant increase of memory CD4+ T cells both in HIV negative and HIV positive subjects (P<O.05). There was significant increase in percentage of CD8+HLA-DR+ (P<O.05) T cells in HIY positive subjects with parasites. Increase in resting CD4+ and CD8+ T cells, decline in CD4+HLA-DR+ and CD8+HLADR+ and increase in CD8+CD38+ T cells was observed after treatment in HIV positive subjects. In HIV negative subjects, a significant decline in activated cells and a significant increase in resting CD8+ T cells (P<O.05) was observed after treatment. These data suggest that the difference in the CD8+ T cells might not be attributed to a specific response of these cells to a specific endemic infectious disease. Other factors, which may lead to different adaptive changes in the immune response, could be involved and should be a subject of further study. The study also indicated that intestinal parasitic infections could result in alteration of T cell subset counts and also in up-regulation of T cell acti vation markers in the peIipheral blood. Treatment for the intestinal parasites showed a tendency of reducing activation of the T cell subsets studied suggesting that, together with other community based intervention strategies, it could be used to down regulate the activation process and hence protect the host T cells from being easily attacked by HIV, the major cause of morbidity and mOltality in the country and the developing world at large.enHIV -LThesis