Induction of idiotype-specific suppressor T cells with antigen/antibody complexes.

Abstract

The effects of immune complexes on the antibody response of BALB/c mice to Streptococcus pneumoniae R36a (Pn) were investigated. The cell wall polysaccharide (PnC) extracted from Pn was used to form complexes with TEPC-15, a myeloma protein that binds to phosphorylcholine determinants on the PnC. Complexes formed at equivalence were cultured with splenic T cells from BALB/c mice for 2 d, and then the cells were added to fresh BALB/c spleen cell cultures to test their effect on the antibody response to Pn, a response dominated by the T15 idiotype family. The results indicate that TEPC-15/PnC complexes induced potent suppressor T cells (Ts) whereas cells cultured with free antigen or free antibody alone had no effect on the plaque-forming cell response to Pn. The suppression was specific since the response to control antigens such as sheep erythrocytes was unaffected. The suppression appears to be idiotype-specific since the Ts had a relatively weak (and in some cases no) effect on the anti-Pn response of BALB/c mice that had been suppressed for T15 idiotopes by neonatal injection of a monoclonal anti-T15 antibody, MaId 5-4. Furthermore, cells cultured with TEPC-15/PnC complexes were shown to express specific receptors for TEPC-15 idiotopes. The results indicate that antigen/antibody complexes may have important immunoregulatory effects because they are potent inducers of idiotype-specific Ts.

The antibody response to specific immune complexes is under genetic control and correlates with the expression of a recurrent idiotype.

“…Once the equivalence zone bad been determined, complexes were prepared in antigen excess by adding a 10-fold excess of PnC to a standard amount of TEPC-15. Before use, the complexes were washed twice with 0.85% saline, an aliquot was dissolved in 0.1 N NaOH, and the protein concentration was determined as described previously (13). The amount of complex used was based on the concentration of protein in the complex.…”

“…The AB1-2 (anti-T15) hybridoma cell line was generously provided by Dr. John Kearney, University of Alabama, Birmingham, AL. The AB1-2 mAb and the TEPC-15 myeloma protein were partially purified from ascites fluid as described elsewhere (13).…”

Size and structure of antigen-antibody complexes: thermodynamic parameters

“…For example, larger complexes more readily fix and activate complement (Doekes et al, 1984) and are more readily phagocytized and removed from the circulation by the reticuloendothelial system (Espinoza, 1983;Segal et al, 1983). Ag-Ab complex size and composition have been shown to directly affect single cell events such as histamine degranulation (Menon et al, 1986) as well as more complex physiological events such as those that lead to immunosuppression (Reisberg & Rossen, 1981;Caulfield et al, 1983). Additionally, size and Ab:Ag ratio affect the ability of complexes to bind to Fc receptors such as protein A (Miyama-Inaba et al, 1987).…”

Detection of bacteria in the presence of antibiotics by using specific monoclonal antibodies to neutralize the antibiotics

“…Anti-penicillin G MAbs (clone 34-S1.1) and antigentamicin MAbs (clone GB26.16) were gifts from Daniel Wilson, Miles Laboratories, Inc., Elkart, Ind. The antibodies (which are of the mouse immunoglobulin G [IgG] class) were purified from ascites fluids by affinity chromatography on protein A-Sepharose columns as described by Goding (5), and the IgG concentration was determined as described elsewhere (3 concentrations ranging from 1 to 4 p.g/ml was used against E. coli. For each concentration of antibiotic, three vials were prepared: one contained a MAb against the antibiotic used, another contained a MAb against an antibiotic of a different group, and the third had no MAb.…”