Antibody Responses to GAT by (Responder × Nonresponder)F1 Spleen Cells Stimulated by Parental GAT-Macrophages

Abstract The development of IgG PFC responses specific for the random terpolymer of l-glutamic acid60-l-alanine30-L-tyrosine10 (GAT) by virgin and immune (responder C57BL/10 × nonresponder DBA/1)F1 spleen cells after stimulation with responder and nonresponder parental or F1 GAT-pulsed macrophages (GAT/Mϕ) in vitro was investigated. Virgin F1 spleen cells developed comparable primary responses to GAT-MBSA and to both parental and F1 GAT-Mϕ. F1 spleen cells from mice immunized with responder or nonresponder parental GAT-Mϕ developed secondary responses only after stimulation with the parental GAT-Mϕ used for immunization or F1 GAT-Mϕ. These observations are consistent with previous observations that spleen cells from mice immunized with syngeneic or allogeneic GAT-Mϕ develop secondary responses only with GAT-Mϕ syngeneic at the I-A subregion of the H-2 complex with the M-ϕ used for priming. By contrast, F1 spleen cells from mice immunized with GAT-MBSA or F1 GAT-Mϕ developed secondary responses after stimulation with either parental or F1 GAT-Mϕ. However, spleen cells from F1 mice immunized with soluble GAT or F1 GAT-Mϕ plus soluble GAT responded only to responder parental or F1 GAT-Mϕ and not to nonresponder parental GAT-Mϕ. These results will be discussed in the context of genetic restrictions regulating Mϕ-T cell interactions in secondary antibody responses, and the possible expression of Ir gene function in Mϕ and/or subsets of T cells in Ft animals. (Support by U.S.P.H.S. Grant AI-13915.)