Regulation of antibody response in vitro. VI. Carrier specific helper cells for IgG and IgE antibody response

Rabbits were primed with DNP coupled Ascaris antigen (DNP Asc) precipitated with aluminium hydroxide gel, received a supplemental immunization with bovine γ globulin (BGG) or ragweed Fr. D (Rag), and their mesenteric lymph node cells were stimulated in vitro with DNP Asc or DNP secondary carrier conjugate (DNP BGG or DNP Rag). IgM, IgG, and IgE antibodies were all formed in vitro, when the cells were stimulated with DNP Asc. Stimulation of the same cells with DNP secondary carrier also resulted in the formation of anti DNP antibodies of the three immunoglobulin classes, when donors of lymphocytes received the carrier with alum. Carrier specific cells generated by the supplemental immunization with the same carrier in complete Freund's adjuvant (CFA) showed helper function for IgM and IgG antibody response but not for IgE antibody response. Similarly, lymph node cells from the rabbits primed with DNP Rag and receiving supplemental immunization with Asc in alum responded to DNP Asc to form IgM, IgG and IgE antibodies. In this system, supplemental immunization with CFA was occasionally effective for IgE antibody response to DNP Asc; however, alum was a more effective adjuvant than CFA to prepare a carrier specific cell population having helper function for IgE antibody response. The helper function of the carrier specific cell population for IgE antibody formation did not have any relationship with either the helper function of the same cell population for IgG antibody response or with the size of the carrier specific cell population estimated by ³H thymidine uptake. Evidence was obtained that lack of IgE antibody response to DNP secondary carrier with the lymphocytes from the CFA group was not due to an increase of precursors of carrier specific antibody forming B cells. The results indicated that carrier specific helper cells for the IgE antibody response were different from those for IgG/IgM antibody response.