title: The role of Ca2+ in activation of mature cytotoxic T lymphocytes for lysis.
abstract: We carried out a detailed analysis of the requirement for Ca2+ in the lysis of target cells by cloned cytotoxic T lymphocytes (CTL). In direct, antigen-specific lysis we always observed an influx of Ca2+ into the CTL concomitant with target cell binding. However, we never observed an increase in CTL Ca2+ content during lectin-mediated lysis, or nonspecific lysis by phorbol myristate acetate-induced CTL. We found that in all three types of lysis (direct, lectin-mediated lysis, C or phorbol myristate acetate-induced) the requirement for Ca2+ in lysis was dictated by the target cell used; the same CTL can kill one target cell in the absence of detectable Ca2+, and absolutely require Ca2+ for the lysis of another target cell. Target cell killing, when it occurred in the absence of Ca2+, was accompanied by microtubule organizing center reorientation in the CTL, showing that this function is not uniformly Ca2+ dependent. These results provide further evidence that Ca2+ is not always required for activation of the lytic pathway in CTL, although Ca2+ may be absolutely required for other CTL functions such as interleukin production or expression of the interleukin 2 receptor.
mesh_terms: D000818:Animals; D001692:Biological Transport; D002118:Calcium / Q000502:physiology*; D002460:Cell Line; D003601:Cytotoxicity Tests, Immunologic; D005110:Extracellular Space / Q000032:analysis; D005260:Female; D007424:Intracellular Fluid / Q000032:analysis; D037102:Lectins / Q000494:pharmacology; D008213:Lymphocyte Activation / Q000187:drug effects; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D008870:Microtubules / Q000648:ultrastructure; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology* / Q000378:metabolism / Q000648:ultrastructure; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D037102:Lectins; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium