Adjuvant enhancement of humoral immune response to chemically inactivated bovine viral diarrhea virus.

Potentiation of the antibody response to inactivated bovine viral diarrhea virus by immunological adjuvants was studied in guinea pigs and cattle. The inactivated bovine viral diarrhea virus alone was demonstrated to be a weak immunogen. Addition of either 2 mg per mL diethylaminoethyl-dextran or 5% alhydrogel to inactivated bovine viral diarrhea virus did not or only slightly stimulated the antibody response; the combined adjuvants induced a significantly higher titer. A higher concentration (20 mg per mL) of diethylaminoethyl-dextran, on the contrary, suppressed the immune potentiation by the dual adjuvants. Combination of Bordetella bronchiseptica and alhydrogel adjuvants stimulated a high titer of antibody. The titer was further elevated upon revaccination and was significantly higher than that induced by alhydrogel alone. In cattle, alhydrogel enhanced the immune response and the additional inclusion of diethylaminoethyl-dextran did not cause a significant potentiation of the immunity. However, the antibody decay rate was significantly slower when stimulated by the combined adjuvants.