Cytolytic activity of murine IL-2-producing CD4+ and CD8+ T cell clones cycles in response to IL-2.
Alloreactive or OVA-reactive cloned murine CD4+ or CD8+ T cells that produce IL-2 exhibit greatly reduced cytolytic activity after being cultured with high concentrations of rIL-2. Furthermore, such cells fail to produce lymphokines or proliferate when stimulated with Ag. The duration of this unresponsiveness to Ag correlates with the concentration of rIL-2 to which the cells were exposed; higher concentrations of rIL-2 prolong the period of unresponsiveness. The presence of ionomycin during the cytolytic assay restores lytic activity to cells rendered unresponsive by exposure to rIL-2. These results suggest that rIL-2-induced unresponsiveness to Ag is a consequence of impairment of a calcium-dependent signal important for cytolysis, proliferation, and lymphokine production. Thus, IL-2 appears to be an important lymphokine that regulates T cell responses downward as well as upward.
McKisic
M D
MD
Department of Pathology, University of Chicago, IL 60637.
Lancki
D W
DW
Cronin
D C
DC
Fitch
F W
FW
D000818:Animals; D015704:CD4 Antigens / Q000032:analysis*; D016827:CD8 Antigens / Q000032:analysis*; D002999:Clone Cells; D003602:Cytotoxicity, Immunologic / Q000187:drug effects*; D007376:Interleukin-2 / Q000096:biosynthesis / Q000494:pharmacology*; D015759:Ionomycin / Q000494:pharmacology; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D011994:Recombinant Proteins / Q000494:pharmacology; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology*
D015704:CD4 Antigens; D016827:CD8 Antigens; D007376:Interleukin-2; D011994:Recombinant Proteins; D015759:Ionomycin