CD8+ and CD45RA+ human peripheral blood lymphocytes are potent sources of macrophage inflammatory protein 1 alpha, interleukin-8 and RANTES.

The chemokines macrophage inflammatory protein 1 alpha (MIP 1 alpha), interleukin-8 (IL-8) and RANTES are potent regulators of leukocyte trafficking. Examination of chemokine secretion by human peripheral blood lymphocytes after stimulation with anti-CD3 or phorbol 12, 13 myristate acetate and ionomycin showed CD8+ cells were the dominant source of MIP 1 alpha and RANTES. Although production of MIP 1 alpha and IL-8 were similar in pharmacologically stimulated CD4+ CD45RA+, CD4+ CD45RO+, and CD8+ CD45RA+ cells, the largest amounts of MIP 1 alpha and RANTES were secreted by CD8+ CD45RO+ lymphocytes. A parallel pattern of prolonged chemokine mRNA expression for at least 18 h after activation was observed in the T cells subsets. These results confirm that human T lymphocytes have a unique capacity for secretion of these three chemokines. In addition, CD8+ cells have an unrecognized role in recruiting cells to sites of inflammation, and adult human CD45RA+ cells have a physiologically significant secretory capacity.