ANTIIDIOTYPIC ANTIBODIES AS SURROGATE ANTIGENS FOR VACCINATING AGAINST THE CATTLE TICK, BOOPHILUS-MICROPLUS

QU13, a monoclonal antibody (mAb) raised against midgut (GM) antigens from Boophilus microplus and shown to recognise antigens which protect cattle from tick challenge was used to immunise cattle and rabbits to produce anti-idiotypic antibodies (AIA). Polyclonal antisera against mAb QU13 were produced in rabbits and cattle. AIA were purified from t hese antisera by affinity chromatography procedures. These purified AI A. were found to block mAb QU13 binding to GM in enzyme-linked immunos orbent assay (ELISA). AIA purified from bovine antiserum elicited an i mmune response in cattle to antigens extracted by detergent from the m idgut of B. microplus (TXGM) after the fourth vaccination (P = 0.06) c ompared with the bovine immunoglobulin (Ig) control. The mean antibody level in the group of experimental cattle vaccinated with AIA purifie d from rabbit antisera was significantly higher (P < 0.03) than that o f bovine Ig control cattle after the fourth vaccination and an anamnes tic response (P < 0.11) occurred in the rabbit AIA vaccinated group of cattle when a single booster dose of 300 mu g of TXGM was given after the first tick challenge. The positive control group of cattle vaccin ated with TXGM were significantly protected (P < 0.05) against tick in festation after the booster dose of 300 mu g of TXGM. The AIA vaccinat ed groups of cattle were not protected against challenge with 20000 la rval ticks either before or after the booster injection of 300 mu g of TXGM.