EFFECT OF ADJUVANTS ON ANTIBODY-RESPONSES OF SHEEP IMMUNIZED WITH RECOMBINANT PILI FROM DICHELOBACTER-NODOSUS

Objective To compare the effects of two oil emulsion adjuvants (incomp lete Freunds adjuvant and a proprietary oil adjuvant), DEAE-dextran, L -tyrosine particles and Quil A on the humoral immune responses of shee p immunised with recombinant pill of Dichelobacter nodosus (strain A). Procedure Antibody titres were studied for up to 32 weeks and were me asured by bacterial agglutination and ELISA. The relative avidity of a ntibodies for pill was determined and the incidence and severity of ad verse reactions at the site of injection of vaccines were recorded. Re sults The oil emulsion adjuvants and Quil A were more effective than e ither DEAE-dextran or L-tyrosine at stimulating antibodies in sheep. T he incidence and severity ct adverse reactions was lower in sheep whic h received vaccines containing either Quit A or DEAE-dextran than in s heep which received vaccines containing oil emulsion adjuvants. L-tyro sine had no adverse effects. Conclusion Quil A was as effective as oil adjuvants at stimulating high levels of antibodies against recombinan t pill in sheep and had the significant advantage of being less irrita nt after subcutaneous injection.