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

The chemokines macrophage inflammatory protein 1α (MIP 1α), 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 1α and RANTES. Although production of MIP 1α and IL‐8 were similar in pharmacologically stimulated CD4⁺ CD45RA⁺, CD4⁺ CD45RO⁺, and CD8⁺ CD45RA⁺ cells, the largest amounts of MIP 1α 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 cell 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.