title: Interferon-gamma-like molecule induces Ia antigens on cultured mast cell progenitors.
abstract: Persisting (P) cells (murine cells that resemble mast cells and grow continuously in vitro for prolonged periods in the presence of a specific growth factor) did not express detectable levels of Ia antigens (murine class II major histocompatibility antigens) when their growth was supported by partially purified P cell-stimulating factor. However, when these Ia-negative P cells were transferred to medium conditioned by concanavalin A-stimulated spleen cells, Ia antigens appeared within 24 hr. The increase in Ia antigens was due to induction of synthesis of Ia antigens by P cells and not to absorption of Ia antigens from the conditioned medium or selective growth of Ia-positive cells from a low number of Ia-positive cells in the original population. The Ia-inducing activity was also found in supernatants from antigen-stimulated cloned T-cell lines, but not from certain T-cell hybridomas or the T lymphoma EL-4. The presence of Ia-inducing activity correlated with the presence of interferon-gamma (IFN-gamma). The gel filtration profiles of IFN-gamma activity and Ia-inducing activity were coincident and corresponded to an apparent molecular weight of 40,000-45,000. Both the IFN-gamma and Ia-inducing activity were destroyed by treatment at pH 2. These results indicate that IFN-gamma or a closely related molecule induces Ia antigens on P cells and suggest that regulation of Ia antigen expression may be an important aspect of the effects of IFN-gamma on the immune and hemopoietic systems.
mesh_terms: D000818:Animals; D001681:Biological Assay; D001853:Bone Marrow / Q000276:immunology; D002478:Cells, Cultured; D002999:Clone Cells; D000939:Epitopes / Q000032:analysis; D005802:Genes, MHC Class II; D007371:Interferon-gamma / Q000276:immunology* / Q000494:pharmacology; D008407:Mast Cells / Q000276:immunology*; D051379:Mice; D008808:Mice, Inbred CBA; D012672:Semliki forest virus / Q000187:drug effects; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D000939:Epitopes; D007371:Interferon-gamma