REGULATORY ROLE OF CD4/L3T4 MOLECULES IN IL-2 PRODUCTION BY AFFECTING INTRACELLULAR CA-2+ CONCENTRATION OF T-CELL CLONE STIMULATED WITH SOLUBLE ANTI-CD3

  • 1 July 1990
    • journal article
    • research article
    • Vol. 145  (1) , 78-84
Abstract
To elucidate the role of CD4 molecule in T cell activation, the effect of anti-CD4 on T cell IL-2 production was examined by using an alloreactive Th clone. The alloreactive T cell used in the present experiments produced IL-2 in response to soluble anti-CD3 .epsilon.-chain (anti-CD3) without accessory cell or insoluble antibody carrier. The IL-2 production was suppressed by the addition of anti-CD4 in cultures. An intracellular free CA2+ concentration ([Ca2+]i) of the T cell clone was elevated by anti-CD3 stimulation, but the elevation was suppressed in the presence of anti-CD4. When the clone was stimulated in Ca2+-free medium, the elevation of [Ca2+]i was not observed. When Ca2+ influx was induced by calcium ionophore A23187 or ionomycin, the clone produced IL-2 in response to anti-CD3 in the presence of anti-CD4. When polyclonal T cell line or several other alloreactive T cell clones were examined for their anti-CD3 response, essentially the same results as mentioned above were obtained. Taken together, these results suggest that the slow and sustained elevation of [Ca2+]i is an essential is an essential signal for IL-2 production of T cells, and this anti-CD4 suppresses the IL-2 production by interfering the [Ca2+]i elevation. The significance of CD4 molecules in murine T cell activation was discussed.