IgG Diphtheria Antitoxin Responses from Human Tonsil Lymphocytes Induced by Anti-γ-Chain Antibodies

Abstract

Abstract Human tonsil lymphocytes were cultured for 24 hr with purified antibodies specific for human IgG heavy chain determinants (anti-γ-chain) and then cultured for 6½ days in Marbrook tubes. IgG diphtheria antitoxin was measured in the culture supernatants by antigen-binding radioimmunoassay. In cultures from eight tonsils, anti-γ-chain stimulated significant IgG antitoxin formation; in each case parallel cultures stimulated with toxoid gave good responses. The specificity of the antibody produced was established by showing that supernatants from cultures stimulated with anti-γ-chain will neutralize toxin. Total IgG in culture supernatants was measured by radioimmunoassay and it was found that cultures stimulated with anti-γ-chain generally produced less total IgG than unstimulated cultures. In time course experiments IgG antitoxin formation increased rapidly after the 3rd day whereas over 50% of the total IgG was produced in the first 3 days. Evidence is presented which suggests that anti-γ-chain acts differently on different groups of B cells.