STCP-1 (MDC) CC-CHEMOKINE ACTS SPECIFICALLY ON CHRONICALLY ACTIVATED TH2 LYMPHOCYTES AND IS PRODUCED BY MONOCYTES ON STIMULATION WITH TH2 CYTOKINES IL-4 AND IL-13

STCP-1 stimulated T cell chemoattractant protein-1 (STCP-1) (macrophag e-derived chemokine; MDC), a recently described CC chemokine for chron ically activated T lymphocytes, was found to act specifically on a sub set of memory CD4 lymphocytes that displayed a Th2 cytokine profile. A lso, STCP-1, thymus and activation regulated chemokine (TARC), eotaxin , and eotaxin-2 acted specifically on in vitro derived Th2 lymphocytes , while IP-10 (IFN-gamma-inducible 10-kDa protein) showed some prefere nce for Th1 lymphocytes, The corresponding receptors for eotaxin, TARC , and IP-10 are also differentially expressed on Th1 and Th2 lymphocyt es. In desensitization Ca flux experiments, TARC and STCP-1 bound to a common receptor and therefore at least one chemokine receptor for STC P-1 is CCR4. STCP-1 expression is restricted to immune cells. Dendriti c cells, B cells, and macrophages produce STCP-1 constitutively, while NK cells, monocytes, and CD4 lymphocytes produce STCP-1 upon appropri ate stimulation. Production of STCP-1 is positively modulated by Th2 c ytokines IL-4 and IL-13 but inhibited by IL-10.