The development of IgG L-glutamic acid -L-alanine -L-tyrosine (GAT)-specific plaque-forming cell responses in vitro by virgin and immune (responder × nonresponder)F spleen cells after stimulation with responder and nonresponder parental GAT-macrophages (Mπ) was investigated. Virgin F spleen cells developed comparable primary responses to both parental GAT-Mπ. By contrast, F spleen cells from mice immunized with GAT or responder parental GAT-M developed secondary responses after stimulation with only responder parental GAT-Mπ Spleen cells from F mice immunized with nonresponder parental GAT-Mπ developed secondary responses to these GAT-Mb, but failed to respond to respender parental GAT-Mπ These results are discussed in the context of genetic restrictions regulating Mπ-T-cell interactions in secondary antibody responses and the possible expression of Ir-gene function in Mπ. © American Society for Clinical Pathology. 60 30 10 1 1 1 1
