Delayed appearance of the catalytic activity by immunization of a rabbit compared with the hapten binding

Polyclonal antibodies catalyzing the hydrolysis of carbonate ester were generated by immunizing a rabbit with hapten(4-nitrophenyl phosphate II) conjugated to keyhole limpet hemocyanin. The hydrolytic activity of IgG purified from antisera exhibited plateu one month later than the simple hapten-binding. The affinity of IgG with substrate increased even after the hapten-binding reached plateu. These suggest a strategy to generate good polyclonal catalytic antibodies and the day to fuse spleen cell with myeloma cell to get good monoclonal catalytic antibodies.