ARE CD8 T-CELLS INVOLVED IN CONTROL OF AFRICAN TRYPANOSOMIASIS IN A NATURAL HOST ENVIRONMENT

Murine models have suggested that CD8 T cells might play a major paras ite-promoting role in African trypanosomiasis. To assess the role of t hese cells in a natural host environment. we have depleted CD8 cells f rom Boran cattle in vivo and subsequently infected these animals with Trypanosoma congolense by tsetse fly challenge. Following administrati on of a mouse monoclonal anti-bovine CD8 antibody, we have been able t o achieve a depletion of more than 99.9% in peripheral blood, spleen, prescapular lymph nodes, prefemoral lymph nodes, mesenteric lymph node s and Peyer's patches. Depletion could be maintained over a 4-5-week i nfection period. Despite the almost total absence of CD8 cells, no eff ect whatsoever was observed on parasitemia. In addition, anemia, which is the main factor determining the mean survival time in cattle was n ot affected by the CD8 depletion.