T1 ST2 IS PREFERENTIALLY EXPRESSED ON MURINE TH2 CELLS, INDEPENDENT OF INTERLEUKIN-4, INTERLEUKIN-5, AND INTERLEUKIN-10, AND IMPORTANT FOR TH2 EFFECTOR FUNCTION/

T helper (Th) cells can be categorized according to their cytokine exp ression. The differential induction of Th cells expressing Th1 and/or Th2 cytokines is key to the regulation of both protective and patholog ical immune responses. Cytokines are expressed transiently and there i s a lack of stably expressed surface molecules, significant for functi onally different types of Th cells. Such molecules are of utmost impor tance for the analysis and selective functional modulation of Th subse ts and will provide new therapeutic strategies for the treatment of al lergic or autoimmune diseases. To this end, we have identified potenti al target genes preferentially expressed, ih Th2 cells, expressing int erleukin (IL)-4, IL-5, and/or IL-10 but not interferon-gamma. One such gene, T1/ST2, is expressed stably on both Th2 clones and Th2-polarize d cells activated in vivo or in vitro. T1/ST2 expression is independen t of induction by IL-4, IL-5, or IL-10. T1/ST2 plays a critical-oh in Th2 effector function. Administration of either a mAb against T1/ST2 o r recombinant T1/ST2 fusion protein attenuates eosinophilic inflammati on of the airways and suppresses IL-4 and IL-5 production in vivo foll owing adoptive transfer of Th2 cells.