Activation of Human T Lymphocytes by Leishmania Lipophosphoglycan

Abstract

This study describes Leishmania antigen-induced activation of lymphocytes isolated from Kenyan donors, previously treated for visceral leishmaniasis. and from Danish and Kenyan controls. Peripheral blood mononuclear cells (PBMC) from cured Kala-Azar patients proliferated and produced Interferon-γ in vitro in response lo lipophosphoglycan (LPG) isolated from Leishmania major. The proliferative response was mainly due lo activation of Cn2-posilive T cells, PBMC from controls did not respond to LPG. hut to sonicates prepared from both L. major and L. donovani promastigotes. The surface glycoprotein GP 63 failed lo activate PBMC from any of the donors tested. These results show that the individuals cured from visceral leishmaniasis had expanded T-cell clones recognizing LPG. conceivably as a result of Leishmania infection. The LPG preparation was without detectable protein contamination. Thus, the results suggest that human T lymphocytes can respond to glycolipid antigens.