title: Monoclonal antibodies to interferon-gamma inhibit interleukin 2-dependent induction of growth and maturation in lectin/antigen-reactive cytolytic T lymphocyte precursors.
abstract: In this study we tested the effect of monoclonal antibodies (moAb) AN-18 to murine IFN-gamma on the generation of cytolytic T cells (CTL) from a homogeneous population of precursor cells (CTL-P). As responder cells, highly purified Lyt-2+ C57BL/6 lymph node T cells were used that had been positively selected by flow cytofluorometry on a cell sorter. Lyt-2+ cells were set up in bulk culture or in limiting dilution (LD) either with Con A or with P815 tumor cells as antigen and recombinant human interleukin 2 (rec.hIL 2) in the presence or absence of moAb AN-18 and tested for growth and development of CTL. The results show that moAb AN-18 but not the unrelated moAb AN-37 diminished or abrogated proliferative and cytolytic responses of Lyt-2+ lymphocytes to lectin and rec.hIL 2 in a dose-dependent manner. The inhibitory activity of the antibodies could be abolished by neutralizing moAb AN-18 with recombinant murine IFN-gamma (rec.mIFN-gamma) before their addition to culture. Kinetic analysis shows that the inhibitory effect of moAb AN-18 is only optimal when added at the beginning of culture or up to 48 hr after initiation. The frequencies of CTL-P responding either to Con A or to P815 tumor cells and rec.hIL 2 were reduced up to 10-fold in the presence of moAb AN-18. The inhibitory capacity of moAb AN-18 was also operative in cultures containing on the average one antigen-specific CTL-P. Together with the finding that activated CTL-P secrete IFN-gamma in response to rec.hIL 2 in a dose-dependent manner, the data suggest that endogenous IFN-gamma collaborates with exogenous IL 2 in the induction of CTL-P. The generation of CTL may therefore represent a case of autocrine growth regulation of normal lymphocytes, in which the same cell synthesizes and responds to its own factor.
authors.forename: M M
authors.initials: MM
authors.lastname: Simon
authors.forename: U
authors.initials: U
authors.lastname: Hochgeschwender
authors.forename: U
authors.initials: U
authors.lastname: Brugger
authors.forename: S
authors.initials: S
authors.lastname: Landolfo
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000502:physiology*; D000937:Antigen-Antibody Reactions; D000950:Antigens, Ly; D002469:Cell Separation; D003208:Concanavalin A / Q000276:immunology; D003601:Cytotoxicity Tests, Immunologic; D005434:Flow Cytometry; D007108:Immune Tolerance; D007371:Interferon-gamma / Q000276:immunology* / Q000494:pharmacology; D007376:Interleukin-2 / Q000502:physiology*; D008213:Lymphocyte Activation; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D010641:Phenotype; D011994:Recombinant Proteins / Q000276:immunology; D013234:Stem Cells / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000145:classification / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D000950:Antigens, Ly; D007376:Interleukin-2; D011994:Recombinant Proteins; D003208:Concanavalin A; D007371:Interferon-gamma