DIFFERENTIAL REGULATION OF IL-13 AND IL-4 PRODUCTION BY HUMAN CD8(-CELL CLONES AND EBV-TRANSFORMED B-CELLS() AND CD4(+) T(H)0, T(H)1 AND T(H)2 T)

In the present study, the requirements and characteristics for the pro duction of IL-13 by human T cells, T cell clones and B cells were dete rmined and compared with those of IL-4, IL-13 was produced by human CD 4(+) and CD8(+) T lymphocyte subsets isolated from peripheral blood mo nonuclear cells and by CD4(+) and CD8(+) T cell clones, CD4(+) T cell clones belonging to ThO, T(h)1-like and Th-2-like subsets produced IL- 13 following antigen-specific or polyclonal activation, In addition, E BV-transformed B cell lines expressed IL-13 mRNA and produced small am ounts of IL-13 protein, Expression of IL-13 mRNA and production of IL- 13 protein by peripheral blood T cells and T cell clones was induced r apidly and was relatively long lasting, whereas IL-4 production by the se cells was transient, In addition, IL-13 mRNA expression was induced by modes of activation that failed to induce IL-4 mRNA expression, IL -13 shares many biological activities with IL-4 which is compatible wi th the notion that the IL-13 and IL-4 receptors share a common compone nt required for signal transduction, However, IL,-13 lacks the T cell- activating properties of IL-4, Here we have shown that this is related to the fact that T cells fail to bind radiolabeled IL-13 and do not e xpress the IL-13-specific receptor component, Taken together, these re sults indicate that the differences in expression and biological activ ities of IL-4 and IL-13 on T cells may have consequences for the relat ive roles of these cytokines in the immune response.