Proliferative and cytokine responses of human T lymphocytes isolated from human immunodeficiency virus-infected patients to the major surface glycoprotein of Pneumocystis carinii.

The current study examined the proliferative capacity and cytokine secretion pattern of peripheral blood mononuclear cells (PBMC) from human immunodeficiency virus type 1 (HIV-1)-infected patients in response to the major surface glycoprotein (MSG) of Pneumocystis carinii. PBMC from AIDS patients with <200 CD4 cells/mL had significantly less proliferative responses to MSG than did healthy controls. Cytokine analysis indicated that interferon-gamma secreted in response to MSG was also significantly less. There was no significant difference in interleukin-4 levels following incubation with MSG between any of the groups; however, all the HIV-infected persons had slightly elevated levels. When the CDC class C3 patients who had a previous episode of P. carinii pneumonia were compared with those who had not had a previous episode, there was a significant increase in the proliferative response to MSG and in interleukin-4 secretion. CDC class C3 patients who had a previous episode of P. carinii pneumonia showed a predominately Th2 response to MSG.