title: A lymphokine that activates the cytolytic program of both cytotoxic T lymphocyte and natural killer clones.
abstract: A 10-12 kD lymphokine, herein termed TCAF, was recently shown to be secreted from Th after crosslinking of their antigen/MHC (T3-Ti) receptors. TCAF stimulates resting T lymphocyte proliferation via binding to surface components of the T11 pathway. To determine whether TCAF could induce antigen-independent activation of the lytic machinery of cytotoxic cells, the present studies were conducted. In the presence of TCAF, both T8+ class I MHC-specific and T4+ class II MHC-specific cytotoxic T cell clones were induced to kill targets, including those lacking the appropriate MHC molecules. This effect was unique to TCAF, since IL-1, IL-2, IFN-gamma could not stimulate lytic activity. Furthermore, both T3+T11+ and T3-T11+ NK clones were triggered to lyse NK-resistant target cells. These findings suggest that TCAF can function in an antigen-independent fashion to amplify cytotoxic effector responses.
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology; D002999:Clone Cells / Q000187:drug effects; D003601:Cytotoxicity Tests, Immunologic; D006680:HLA Antigens / Q000276:immunology; D015793:HLA-B7 Antigen; D007376:Interleukin-2 / Q000302:isolation & purification / Q000494:pharmacology; D007694:Killer Cells, Natural / Q000187:drug effects* / Q000276:immunology; D008213:Lymphocyte Activation / Q000187:drug effects*; D008222:Lymphokines / Q000494:pharmacology*; D013602:T-Lymphocytes, Cytotoxic / Q000145:classification / Q000187:drug effects* / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D006680:HLA Antigens; D015793:HLA-B7 Antigen; D007376:Interleukin-2; D008222:Lymphokines