Interleukin 4 enhances the ability of antigen-specific B cells to form conjugates with T cells.
T cell-B cell conjugates are formed when trinitrophenyl-specific B cells are exposed to trinitrophenyl-ovalbumin and ovalbumin-specific T hybridoma cells. The proportion of conjugates was increased two- to threefold when antigen-pulsed trinitrophenyl-specific B cells, but not T cells, were pre-exposed to interleukin 4. Antigen-specific B cells pretreated with antigen and interleukin 4 and cultured in the presence of specific T helper cells also produced a larger proportion of antibody-secreting cells as compared to cells pretreated with antigen alone. The interleukin 4-induced enhancement of T/B conjugate formation occurred over a wide range of antigen concentrations, was dependent on the concentration of interleukin 4, and was inhibited by the monoclonal anti-interleukin 4 antibody, 11B11. The importance of Ia antigens in the enhancement of conjugate formation and generation of antibody-secreting cells is suggested by a) the fact that the interleukin 4-mediated increase in the density of Ia antigens on the antigen-specific B cells correlated with their enhanced ability to form T/B conjugates, b) the kinetics of the interleukin 4-mediated increase in conjugate formation and surface Ia expression were similar, c) 10- to 20-fold higher concentrations of anti-I-A antibody were required to inhibit T/B conjugate formation by 50% with interleukin 4-treated antigen-specific B cells compared with untreated antigen-specific B cells, and d) interferon-gamma, which inhibits the interleukin 4-mediated increase in Ia antigens, inhibited the interleukin 4-induced enhancement of T/B conjugate formation. These results indicate that the interleukin 4-induced increase in the expression of Ia antigens on B cells plays an important role in the enhancement of T/B cell interactions and the subsequent differentiation of antigen-specific B cells into antibody-secreting cells.
D000818:Animals; D000917:Antibody Formation; D001402:B-Lymphocytes / Q000187:drug effects* / Q000276:immunology; D005260:Female; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D006825:Hybridomas; D015847:Interleukin-4; D007378:Interleukins / Q000494:pharmacology*; D008211:Lymphocyte Cooperation / Q000187:drug effects*; D051379:Mice; D008807:Mice, Inbred BALB C; D010047:Ovalbumin / Q000276:immunology; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*
D000949:Histocompatibility Antigens Class II; D007378:Interleukins; C038600:trinitrophenyl-ovalbumin; D015847:Interleukin-4; D010047:Ovalbumin