EFFECTS OF ADJUVANTS ON BOVINE HUMORAL AND CELLULAR-RESPONSES TO HYPODERMIN-A

Hypodermin A, a serine protease of the first-instar larva of the commo n cattle grub, Hypoderma lineatum (Villers), when formulated with comp lete Freund's adjuvant and administered to naive calves, will elicit p rotective immunity defined by an increase in in vivo larval mortality. This study evaluated two veterinary acceptable adjuvants, alhydrogel and amphigen (alone and in combination), for suitability as an adjuvan t for hypodermin A. Complete Freund's adjuvant (CFA) is not an accepta ble adjuvant for use because of adverse reactions at the injection sit e. The veterinary acceptable adjuvants were not as effective as CFA in inducing an antibody response as detected in the peripheral circulati on. Of the adjuvants evaluated, the mixture of alhydrogel and amphigen induced the highest serum antibody response to hypodermin A. All adju vants evaluated induced comparable immediate-type skin test responses, and the mixture of alhydrogel and amphigen was most comparable with C FA in terms of delayed-type skin reaction and resultant cellular infil tration at the reaction site. Although the mixture of alhydrogel and a mphigen, when compared with CFA, did not elicit comparable levels of r esponsiveness in all parameters tested, the overall performance of the mixture suggests it to be worthy of further efficacy investigation in a vaccine formulation with hypodermin A.