Antibody responses to trinitrophenyl (TNP)- l-glutamic acid 60- l-alanine 30- l-tyrosine 10 (GAT) in microcultures: Anti-hapten and anti-carrier responses appear to be under separable control

Abstract

We have previously reported that the IgM anti-hapten plaque-forming cell (PFC) response to trinitrophenyl (TNP)-conjugated l-glutamic acid 60- l-alanine 30- l-tyrosine 10 (GAT) is not under conventional Ir gene control in an in vitro microculture system. To explore this phenomenon, we examined both the anti-hapten and anti-carrier antibody responses to TNP-GAT in the microculture supernatants using a solid-phase radioimmunoassay (RIA). We show that splenocytes from GAT-responder BALB/c mice produce anti-hapten and anti-carrier antibody responses to TNP-GAT in microcultures, while splenocytes from GAT-nonresponder DBA/ 1 mice produce anti-hapten but not anti-carrier responses to TNP-GAT in these culture conditions. We further demonstrate that supernatants from rat splenocyte cultures stimulated by concanavalin A (Con A) similarly drive unprimed, T-lymphocyte-depleted splenocytes to produce anti-hapten but not anti-carrier antibody responses to TNP-GAT in microcultures. This observation suggests that T-cell-B-cell contact may not be required for the generation of anti-hapten responses by splenocytes to TNP-GAT in microcultures and may explain the absence of conventional Ir gene control of such responses in these cultures.