Role of interleukin 1 in the activation of T lymphocytes.
The activation of T lymphocytes requires their stimulation via clonotypic antigen receptors as well as nonantigen-specific costimulators, the best defined of which is the cytokine interleukin 1 (IL-1). Recent studies have shown that murine CD4+ helper T lymphocytes consist of two nonoverlapping subsets that selectively utilize interleukin 2 (IL-2) or interleukin 4 as their autocrine growth factors and are called Th1 and Th2 cells, respectively. We now show that IL-1 functions as a costimulator for the proliferation of Th2 but not of Th1 clones and only Th2 cells express high-affinity receptors for IL-1. Secretion of autocrine growth-promoting lymphokines by Th1 and Th2 cells occurs after stimulation via the antigen receptor-CD3 complex and is neither dependent on nor affected by IL-1. These findings suggest that the activation of T lymphocytes can be divided into two stages, lymphokine secretion and proliferation, and only proliferation requires costimulators such as IL-1. Moreover, the prevailing view that IL-1 functions as a costimulator by inducing secretion of IL-2 or expression of IL-2 receptors may not be generally applicable, because IL-2-producing Th1 clones do not express receptors for IL-1 and are insensitive to this cytokine.
Lichtman
A H
AH
Department of Pathology, Brigham and Women's Hospital, Boston, MA.
Chin
J
J
Schmidt
J A
JA
Abbas
A K
AK
D000945:Antigens, Differentiation, T-Lymphocyte; D002455:Cell Division / Q000187:drug effects; D002999:Clone Cells / Q000032:analysis; D005786:Gene Expression Regulation; D006801:Humans; D007375:Interleukin-1 / Q000502:physiology*; D015847:Interleukin-4; D007378:Interleukins / Q000096:biosynthesis / Q000235:genetics; D008213:Lymphocyte Activation; D008222:Lymphokines / Q000096:biosynthesis; D013601:T-Lymphocytes / Q000276:immunology*
D000945:Antigens, Differentiation, T-Lymphocyte; D007375:Interleukin-1; D007378:Interleukins; D008222:Lymphokines; D015847:Interleukin-4