Upregulation of integrin alpha 6/beta 1 and chemokine receptor CCR1 by interleukin-12 promotes the migration of human type 1 helper T cells

CD4(+) T helper 1 (Th1) cells and Th2 cells are distinguished based on the pattern of cytokines they are able to produce. Selectin ligands and chemoki ne receptors are differentially expressed in Th1 and Th2 cells, providing a basis for tissue-specific recruitment of helper T-cell subsets. However, t he modes and mechanisms regulating tissue-specific localization of Th1 and Th2 cells are still largely unknown. Here, we show the preferential express ion on Th1 cells of the integrin alpha 6/beta 1, which is distinctly regula ted by the Th1-inducing cytokines interleukin-12 (IL-12) and interferon-alf a (IFN-alpha). The pattern of integrin alpha 6/beta 1 regulation closely mi rrors that of the chemokine receptor CCR1, Analysis of signal transducer an d activator of transcription 4 (Stat4) activation by IL-12 and IFN-alpha sh ows distinct signaling kinetics by these cytokines, correlating with the pa ttern of CCR1 and integrin alpha 6/beta 1 expression. Unlike IFN-a, the abi lity of IL-12 to generate prolonged intracellular signals appears to be cri tical for inducing integrin alpha 6/beta 1 upregulation in Th1 cells, The e xpression and upregulation of CCR1 and alpha 6/beta 1 integrin promotes the migration of Th1 cells. These findings suggest that the exquisite regulati on of integrin alpha 6/beta 1 and CCR1 may play an important role in tissue -specific localization of Th1 cells. (C) 1999 by The American Society of He matology.