Effect of preimmunization with native and methylated carrier on class-specific anti-hapten and anti-carrier antibody response

Effects of priming with bovine serum albumin (BSA) and methylated BSA (MBSA) on the primary anti-2,4-dinitrophenyl (DNP) response were studied in the chicken. A new radioimmunoassay of class-specific antibodies (RIACA) was used to quantitate IgM and IgG antibodies against BSA and DNP. The anti-DNP antibody response after priming with BSA was dose-dependent: large doses of BSA suppressed and the smallest dose augmented it. In contrast, no dose dependence was observed between MBSA and the anti-hapten response. All doses of MBSA enhanced the primary anti-DNP antibody response of both immunoglobulin classes. No corresponding differences in anti-BSA antibodies were observed between BSA- and MBSA-primed groups. This suggests that the anticarrier antibodies as such are not the agent suppressing the anti-hapten response when large doses of native carrier are used for priming. A more probable explanation of this phenomenon is a competition between carrier-specific B cells and hapten-specific B cells for common T cells. A less obvious explanation is the generation of more helper cells or less suppressor cells when priming with MBSA than with BSA.