title: Gamma interferon-mediated cytotoxicity related to murine Chlamydia trachomatis infection.
abstract: After infection with the mouse pneumonitis agent (MoPn; murine Chlamydia trachomatis), heterozygous (nu/+) but not nude athymic (nu/nu) mice produced enhanced amounts of gamma interferon (IFN-gamma) in vitro in response to MoPn antigen that exhibited cytotoxic activity when added to host cells already infected with chlamydiae. Antibody-complement lysis showed the cytotoxic activity to be dependent, at least in part, on L3T4+ T cells for production. The cytotoxic responses were directed primarily against Chlamydia-infected target cells, but a second type of toxicity was demonstrable against uninfected target cells after treatment of the generating cell population with anti-Lyt-2 antibody plus complement at certain time points after infection. This additional nonspecific cytotoxic activity was presumably due to a second factor (factor X) acting in concert with IFN-gamma. Lyt-2+ cells, however, also were shown to play a role in IFN-gamma production and cytotoxicity directed against infected targets at later time points after infection. Neutralization of IFN-gamma in the samples containing cytotoxic activity abrogated the cytotoxicity against both infected and uninfected targets, but cloned murine IFN-gamma exhibited toxicity in a dose-dependent manner only against infected target cells. The data provides evidence that cytotoxicity against infected targets is due to antigen-specific induction of IFN-gamma, but other cytokine activity, most demonstrable after removal of Lyt-2.2+ cells and cytotoxic to uninfected targets, also is present.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000942:Antigens, Bacterial / Q000276:immunology; D000945:Antigens, Differentiation, T-Lymphocyte / Q000276:immunology; D002690:Chlamydia Infections / Q000276:immunology*; D002692:Chlamydia trachomatis / Q000276:immunology*; D003602:Cytotoxicity, Immunologic / Q000187:drug effects; D007111:Immunity, Cellular / Q000187:drug effects; D007371:Interferon-gamma / Q000494:pharmacology / Q000502:physiology*; D051379:Mice; D008819:Mice, Nude; D011994:Recombinant Proteins; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D000942:Antigens, Bacterial; D000945:Antigens, Differentiation, T-Lymphocyte; D011994:Recombinant Proteins; D007371:Interferon-gamma