title: Inhibition of the helper function of murine T cells with Fab'-anti-L3T4 ricin A chain immunotoxin.
abstract: The ability of Fab'-anti-L3T4 A chain-containing immunotoxins to inhibit the helper function of keyhole limpet hemocyanin-specific T helper lymphocytes was evaluated. Keyhole limpet hemocyanin-specific T helper cells were prepared from the lymph nodes of primed mice and were enriched for T cells. Enriched populations of trinitrophenyl-specific B cells were prepared from spleens of normal mice. In the presence of antigen, the keyhole limpet hemocyanin-specific T helper cells were able to induce proliferation and differentiation of the trinitrophenyl-specific B cells. However, when the T helper cells were first treated with an immunotoxin composed of Fab' fragments of anti-L3T4 antibody coupled to ricin A chain (Fab'-anti-L3T4-A), they failed to induce proliferation and differentiation of the antigen-specific B cells. The concentrations of Fab'-anti-L3T4-A required to inhibit T cell help for the proliferation and differentiation of trinitrophenyl-specific B cells by 50% were 1 X 10(-9)M and 4 X 10(-10) M, respectively. Fab'-anti-L3T4 antibody alone did not inhibit T cell-induced B cell proliferation and differentiation by 50% at greater than 100-fold higher concentrations.
mesh_terms: D000818:Animals; D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology; D002469:Cell Separation; D005260:Female; D007140:Immunoglobulin Fab Fragments / Q000008:administration & dosage / Q000276:immunology; D007075:Immunoglobulin M / Q000378:metabolism; D000922:Immunotoxins / Q000008:administration & dosage; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C / Q000276:immunology; D012276:Ricin / Q000008:administration & dosage / Q000494:pharmacology*; D013154:Spleen / Q000166:cytology; D006377:T-Lymphocytes, Helper-Inducer / Q000187:drug effects* / Q000276:immunology
chemical_list: D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; D007140:Immunoglobulin Fab Fragments; D007075:Immunoglobulin M; D000922:Immunotoxins; D012276:Ricin