title: Selective abrogation of antigen-specific human B cell responses by antigen-ricin conjugates.
abstract: The feasibility of selectively eliminating human antigen-specific B cell responses by treating cells in vitro with antigen covalently linked to a cell toxin was examined. Tetanus toxoid (TT) was conjugated to the toxin ricin via a thioether linkage. Peripheral blood mononuclear cells from recently immunized subjects were preincubated for 2 h with TT-ricin in the presence of lactose. Antigen was then removed, and the cells from recently immunized subjects were preincubated for 2 h with TT-ricin in the presence of lactose. Antigen was then removed, and the cells were stimulated with pokeweed mitogen to induce antibody production. TT-specific antibody production was completely abrogated by preincubation with TT-ricin but not by TT alone or a mixture of TT and ricin. In contrast, polyclonal immunoglobulin production was not diminished by TT-ricin. This selective abrogation was also seen when B cells alone were preincubated with TT-ricin and a source of T cell help was later provided. T cell blastogenic responses to TT remained intact after TT-ricin exposure. Thus, antigen-toxin conjugates are capable of selectively eliminating specific antibody-producing B cell clones, while leaving intact the remainder of the B cell repertoire.
mesh_terms: D000293:Adolescent; D000328:Adult; D000917:Antibody Formation; D000941:Antigens; D001402:B-Lymphocytes / Q000276:immunology*; D002469:Cell Separation; D006801:Humans; D009000:Monocytes / Q000276:immunology; D012276:Ricin; D013745:Tetanus Toxoid / Q000276:immunology
chemical_list: D000941:Antigens; D013745:Tetanus Toxoid; D012276:Ricin