Monokine production by human T cells; IL-1 alpha production restricted to memory T cells.

The production of cytokines is a key event of inflammation. In this report we demonstrate that normal human T cells are capable to produce IL-1 alpha, IL-6, and TNF-alpha, cytokines formerly considered to be monokines. This production was optimal after stimulation with a combination of anti-CD2, PMA, and anti-CD28. All three cytokines were produced in a bioactive form. Both naive (CD4+CD45RA+) and memory (CD4+CD45RO+) subsets of T cells were shown to produce similar amounts of IL-6 and TNF-alpha. In contrast the production of IL-1 alpha was found to be completely restricted to the CD4+CD45RO+ subset. The finding that T cells are such potent producers of these important mediators of the inflammatory response might be a key observation in the appreciation of the role of T cells in chronic inflammation.