T cell dependence and factor reconstitution of in vitro antibody responses to TNP-B. Abortus and TNP-Ficoll: restoration of depleted responses with chromatographed fractions of a T cell-derived factor.
In vitro anti-trinitrophenyl (TNP) antibody responses to TNP conjugates of killed Brucella abortus organisms (TNP-BA), an antigen previously designated as a type 1 thymus-independent (TI-1) antigen, are markedly diminished after vigorous depletion of T cells, as are the responses to the type 2 TI (TI-2) antigen, TNP-Ficoll. We, therefore, propose that these antigens be redesignated as type 1 and type 2, respectively, to reflect their T cell dependence but to differentiate them from classical T cell-dependent (TD) antigens. T cell-depleted responses to type 1 and type 2 antigens can be restored by the addition of a) EL4 supernatant, b) phenyl-sepharose-purified fractions of EL4 supernatant that are rich in interleukin 2(IL2), and c) pl 4.5-5.5 isoelectric focused (IEF) fractions of EL4 supernatant which are also rich in IL2 activity. Removal of IL2 activity from EL4 supernatant by absorption on IL2-dependent T cells substantially reduced its restorative ability. Whether the active principle in EL4 supernatant activity responsible for restoring responses to type 1 and type 2 antigens is IL2, and whether it acts directly on B cells or by acting on contaminating T cells, is unresolved.
D000818:Animals; D000917:Antibody Formation; D000955:Antigens, T-Independent / Q000276:immunology*; D002003:Brucella abortus / Q000276:immunology; D005260:Female; D005362:Ficoll; D006241:Haptens; D007376:Interleukin-2 / Q000032:analysis; D007525:Isoelectric Focusing; D051379:Mice; D008807:Mice, Inbred BALB C; D013601:T-Lymphocytes / Q000276:immunology*
D000955:Antigens, T-Independent; D006241:Haptens; D007376:Interleukin-2; D005362:Ficoll