A primary in vitro antibody assay for antigen-specific T-suppressor factor: cross-suppression of TNP-specific antibody responses by TMA-specific TsF1.
We have previously shown that phenyltrimethylammonium (TMA)-specific, first-order suppressor T cells (Ts1) and soluble factors extracted from these cells (TsF1) can suppress delayed-type hypersensitivity (DTH) responses. The TsF1, as monitored in the DTH system, was characterized and found to be a single-chain, antigen-binding, I-J+, and Id+ molecule. To monitor TsF1 in an efficient manner, an in vitro antibody system was developed. The studies show that in vitro stimulation of naive A/J spleen cells with the thymic-independent antigen, Brucella abortus, to which TMA and trinitrophenol (TNP) or fluorescein (FL) are coupled (TMA-BA-TNP or TMA-BA-FL), induces significant numbers of anti-TNP or anti-FL plaque-forming cell (PFC) responses. The addition of TMA-specific TsF1 results in the cross-suppression of 30-50% of the total anti-TNP and FL PFC responses. This activity is antigen (TMA) dependent since suppression occurs only when the TMA ligand is present in the culture media. Analysis of the TNP-specific PFC responses in nonsuppressed cultures revealed that 20-35% of the PFC bear the cross-reactive idiotype(s) (CRI) normally associated with anti-TMA antibodies. In cultures containing TMA-TsF1, CRI+PFC are suppressed by 90-100% while the CRI-PFC are suppressed only by 10-30%. Our studies further show that an induction-phase, antigen-binding, CRI+, and I-J+ single-chain factor is responsible for the observed in vitro suppression. The possibility of utilizing this assay to monitor a variety of antigen-specific suppressor factors is discussed.
G S
GS
Jendrisak
S
S
Jayaraman
C J
CJ
Bellone
D000818:Animals; D000917:Antibody Formation; D001665:Binding Sites; D002003:Brucella abortus / Q000276:immunology; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003429:Cross Reactions; D000939:Epitopes / Q000276:immunology*; D006241:Haptens / Q000276:immunology; D006462:Hemolytic Plaque Technique; D007130:Immunoglobulin Idiotypes / Q000276:immunology; D007163:Immunosorbent Techniques; D008297:Male; D051379:Mice; D008805:Mice, Inbred A; D009578:Nitrobenzenes / Q000276:immunology*; D000644:Quaternary Ammonium Compounds / Q000276:immunology*; D013491:Suppressor Factors, Immunologic / Q000032:analysis / Q000378:metabolism / Q000494:pharmacology*; D014301:Trinitrobenzenes / Q000276:immunology*
D000939:Epitopes; D006241:Haptens; D007130:Immunoglobulin Idiotypes; D009578:Nitrobenzenes; D000644:Quaternary Ammonium Compounds; D013491:Suppressor Factors, Immunologic; D014301:Trinitrobenzenes; C009571:phenyltrimethylammonium