THE SPECIFICITY AND AFFINITY OF POLYCLONAL ANTIBODIES RAISED IN RABBITS AGAINST A HAPTEN CONJUGATED TO RABBIT SERUM-ALBUMIN

In this study, rabbit antisera to hapten-rabbit serum albumin conjugat es were investigated regarding antibody titer, affinity, specificity, and affinity distribution. Methyl phosphonic acid p-aminophenyl 1,2,2- trimethylpropyldiester (MATP) served as model hapten. Four MATP-rabbit serum albumin conjugates with various hapten densities (with and with out spacer) were synthesized and used for immunization of rabbits. Ant isera were collected over a 130 day-period and characterized with diff erent ELISA methods. We found that immunogens with rabbit serum albumi n gave antisera with lower titers, but similar affinity as compared to polyclonal or monoclonal antibodies obtained with non-rabbit protein as carrier protein. Immunogens with a low hapten density led to higher final titers without affecting antibody affinity or specificity. Immu nogens containing a bridging group resulted in higher antibody affinit y with a changed specificity. The pattern of antibody affinity distrib ution differed considerably among individual rabbits and showed a non- Gaussian subpopulation distribution.