Influence of the genetic background and carrier protein on the antibody response to GnRH.

A vaccine against the gonadotropin releasing hormone (GnRH) is being developed as an immunological method for the treatment of prostatic enlargement. The work described here was aimed at investigating the influence of the genetic background on immune responses to GnRH conjugated to diphtheria toxoid (DT). Mice of different strains were injected with the conjugate and the antibody levels against GnRH and DT quantitated in order to examine the effect of genetic background on immune responses to the hapten and the carrier. All immunized animals produced antibodies to DT. Anti-GnRH antibodies were generated by all strains of mice except 129. The low anti-GnRH response in the 129 strain mice did not appear to be MHC-linked, as C57BL/6 mice, which bear the same MHC haplotype as 129 mice, were able to generate a strong anti-GnRH response. The non-responsiveness to the hapten (GnRH) in 129 strain mice was overcome by the use of an 'alternate carrier' approach.