COMPARISON OF LYMPHOKINE SECRETION AND MESSENGER-RNA EXPRESSION IN THE CD45RA(+) AND CD45RO(+) SUBSETS OF HUMAN PERIPHERAL-BLOOD CD4(+) AND CD8(+) LYMPHOCYTES

Flow cytometric analysis of human peripheral blood T lymphocytes demonstrated that the majority of the CD4(+) cells were CD29(+) or CD45RO(+) ''mature'' cells while the CD8(+) cells were primarily CD45R4(+) ''naive'' cells. After an initial separation into CD4(+) and CD8(+) cells and a secondary separation into CD45 subsets, lymphokine secretion was assessed after phorbol 12-myristate 13-acetate and ionomycin or fixed anti-CD3 stimulation. Within the respective CD45 subsets, CD4(+) cells produced more interleukin (IL)-2, IL-4, and IL-6; but the CD8(+) cells secreted more interferon-gamma and granulocyte/macrophage-colony-stimulating factor. Tumor necrosis factor-alpha secretion was similar in the matched CD45 subsets. Northern analysis revealed a parallel pattern of lymphokine mRNA expression in the four lymphocyte subsets. These results suggest that human CD8(+) peripheral blood lymphocytes have a significant capacity to secrete lymphokines, and that the low lymphokine production observed in unseparated CD8(+) cells reflects the higher percentage of less functional CD45RA(+) cells.