Staphylococcal superantigens induce lymphotactin production by human CD4+ and CD8+ T cells

Lymphotactin is a potent chemotactic cytokine (chemokine) that is produced by and also attracts T and natural killer (NK) cells. We are studying wheth er chemokines that affect mainly T cells might also regulate immune respons es by preferentially recruiting individual subsets or by affecting cytokine or other chemokine responses. In order to pursue these questions, we need to learn more about the mechanisms regulating lymphotactin production and t he cell types capable of releasing this factor. We used new monoclonal anti bodies against human lymphotactin to develop a sensitive antigen-capture en zyme linked immunoabsorbent assay (ELISA) that measures chemokine levels in culture fluids. Using this capture ELISA, we showed that lymphotactin coul d be produced by CD4+ and CD8 + T cells, but only after T cell-receptor-dep endent stimulation using bacterial superantigens and not after treatment by inflammatory cytokines or lipopolysaccharide (LPS). Our data show that lym photactin production responds mainly to T cell-receptor signals in CD4+ and CD8+ T cells, and suggests a mechanism whereby this chemokine could help t o regulate T cell immune responses. (C) 2001 Academic Press.