REGULATION OF HUMAN T-LYMPHOCYTE CHEMOTAXIS IN-VITRO BY T-CELL-DERIVED CYTOKINES IL-2, IFN-GAMMA, IL-4, IL-10, AND IL-13

There has been a number of conflicting reports regarding the T lymphocyte chemotactic activities of several cytokines. IL-2 and IFN-gamma are known to promote augmentation of immune inflammation, whereas IL-4, IL-10, and IL-13 display immunomodulatory effects on inflammatory cells including inhibition of cytokine production. Their effects on chemotaxis of inflammatory cells are unknown. We observed that IL-1 alpha could induce chemotaxis both in overnight cultured and anti-CD3 mAb-activated T lymphocytes and that overnight culture and anti-CD3 activation increase the number of IL-1R on T lymphocytes. In contrast, IL-8 selectively attracts freshly isolated T lymphocytes. Staurosporine inhibits freshly isolated T lymphocyte chemotaxis toward IL-8, whereas tyrphostin 23 inhibits chemotaxis of overnight cultured and anti-CD3-activated T lymphocytes toward IL-1 alpha. We have found that IL-2 and IL-13 inhibit the chemotactic migration of both CD4(+) and CD8(+) T lymphocytes toward IL-8, and RANTES. IL-4 inhibits only CD8(+) T lymphocyte chemotaxis toward RANTES, IL-8 and IL-10. IL-10 inhibits only CD4(+) T lymphocytes in their chemotactic response toward RANTES and IL-8. IFN-gamma does on the other hand augment the sensitivity of human T lymphocytes to chemotactic stimuli. Thus, our results demonstrate that different proinflammatory cytokines will induce chemotactic migration of T lymphocytes under different circumstances acting through different signaling pathways. The T cell-derived cytokines IL-2, IL-4, IL-10, and IL-13 are able to block further T lymphocyte chemotaxis, thus leading to a focusing of T lymphocytes in an area of T lymphocyte activation. These mechanisms seem relevant in our understanding of the specific and continuous localization of T lymphocytes in allergic and autoimmune disorders.