title: Obligatory role of gamma interferon in T cell-replacing factor-dependent, antigen-specific murine B cell responses.
abstract: The role of gamma interferon (IFN-gamma) in T cell-replacing factor (TRF) activity for antigen-specific plaque-forming cell (PFC) responses in vitro was studied using antibodies to murine IFN-gamma (Mu IFN-gamma). TRF activity was present in supernatants (Sn) of Con A- or mixed leukocyte reaction-stimulated murine spleen cells as well as in an IL-2-rich fraction of phytohemagglutinin-stimulated human peripheral blood lymphocyte Sn and in the Sn of the Gibbon T lymphoma MLA-144. The human TRF was highly active with cells from nu/nu mice and normal mice but not with cells from animals with the xid immunologic defect, similar to the activity of murine TRF. Antibodies to IFN-gamma consisted of hyper-immune rabbit antisera, IFN-gamma affinity-purified rabbit immunoglobulin and an interspecies hybridoma specific for Mu IFN-gamma. The results show that the activities of all preparations of TRF are markedly diminished or abrogated by antibody to Mu IFN-gamma but not by antibodies to human IFN-gamma (Hu IFN-gamma), nor by normal rabbit sera or purified rabbit Ig. The degree of inhibition was dose dependent and was quantitatively reversed by the addition to the cultures of recombinant-derived Mu IFN-gamma (Mu rIFN-gamma) but not Hu rIFN-gamma. This reversal was fully antigen specific and thus not attributable to polyclonal B cell activation by IFN-gamma, which is inactive alone in the TRF assay. Kinetic analysis shows that IFN-gamma must act by 24-48 h to produce PFC responses at 4 d. Together, the data demonstrate that IFN-gamma is a necessary mediator for TRF effects and that IFN-gamma is induced by TRF from T-depleted murine spleen cells in sufficient quantity to support large antibody responses. The source of this IFN-gamma may be the potent natural killer cells that are induced in cultures stimulated with TRF.
authors.forename: M
authors.initials: M
authors.lastname: Brunswick
authors.forename: P
authors.initials: P
authors.lastname: Lake
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000502:physiology; D001402:B-Lymphocytes / Q000276:immunology*; D001667:Binding, Competitive; D000939:Epitopes / Q000276:immunology*; D006462:Hemolytic Plaque Technique; D007106:Immune Sera / Q000494:pharmacology; D007136:Immunoglobulins / Q000502:physiology; D007371:Interferon-gamma / Q000096:biosynthesis / Q000276:immunology / Q000502:physiology*; D007376:Interleukin-2 / Q000502:physiology; D015848:Interleukin-5; D007694:Killer Cells, Natural / Q000276:immunology; D008213:Lymphocyte Activation; D008222:Lymphokines / Q000502:physiology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008808:Mice, Inbred CBA; D008819:Mice, Nude; D011817:Rabbits; D013154:Spleen / Q000166:cytology; D013997:Time Factors
chemical_list: D000911:Antibodies, Monoclonal; D000939:Epitopes; D007106:Immune Sera; D007136:Immunoglobulins; D007376:Interleukin-2; D015848:Interleukin-5; D008222:Lymphokines; D007371:Interferon-gamma