title: Inhibition of human lymphocyte-mediated mitogen-induced cytotoxicity of murine L-929 cells by heterologous anti-human lymphotoxin antisera in vitro.
abstract: Heterologous anti-human lymphotoxin (LT) antisera have been employed to investigate the role of LT in mitogen-(Con-A, PHA) induced destruction of murine L-929 cells by human lymphocytes in vitro. These various antisera will effectively neutralize human LT molecules associated with the stable (70 to 90,000 dalton) alpha-LT class of cytotoxin (anti-alpha-LT), the more unstable (35 to 50,000 dalton) beta-LT class of cytotoxins (anti-beta-LT), and antisera which will neutralize all classes of these cytotoxins in vitro, anti-whole supernatant (anti-W.S.). These anti-LT sera will greatly inhibit lysis of L-929 cells by using mitogen-activated human effector lymphocytes in vitro. This blocking was shown to be mediated by whole serum, purified IgG, or IgG-Fab fragments, which had been extensively absorbed with bovine serum, human serum, mitogens, and normal human lymphocytes. Inhibition of lysis was not apparently due to interference with either lymphocyte-target cell contact or lymphocyte activation step(s). The blocking effects of these sera were also shown to occur during the lymphocyte-independent phase of the lytic reaction. These data support the concept that the lymphocyte deposits an LT-like effector molecule on the target-L cell surface during the lymphocyte-dependent phase, which mediates cell lysis at a later time during the lymphocyte-independent phase.
mesh_terms: D000818:Animals; D000910:Antibodies, Heterophile; D001667:Binding, Competitive; D003208:Concanavalin A / Q000494:pharmacology; D003601:Cytotoxicity Tests, Immunologic; D006801:Humans; D007140:Immunoglobulin Fab Fragments; D007074:Immunoglobulin G; D066298:In Vitro Techniques; D007700:Kinetics; D007739:L Cells; D037102:Lectins / Q000494:pharmacology; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000276:immunology*; D008233:Lymphotoxin-alpha / Q000276:immunology*; D051379:Mice
chemical_list: D000910:Antibodies, Heterophile; D007140:Immunoglobulin Fab Fragments; D007074:Immunoglobulin G; D037102:Lectins; D008233:Lymphotoxin-alpha; D003208:Concanavalin A