Adjuvanticity of dimethyl dioctadecyl ammonium bromide, complete Freund's adjuvant and Corynebacterium parvum with respect to host immune response to coccidial antigens.

Immune response of chickens to Eimeria was investigated following immunization with coccidial antigens in combination with various immunological adjuvants. The adjuvanticity of dimethyl dioctadecyl ammonium bromide (DDA) was comparable to that of two other adjuvants known to stimulate cell-mediated immunity: complete Freund's adjuvant (CFA) and Corynebacterium parvum. However, DDA is considered less toxic than CFA and appeared to evoke longer-lasting immunity than C. parvum. In general, intramuscular immunization of chickens with merozoite antigens in DDA engendered higher protective immunity than did oral immunization. Immunization of chickens with merozoite antigens in CFA, DDA, or C. parvum engendered serum IgG and biliary secretory IgA (sIgA) antibody responses, as well as coccidial antigen-specific T-cell lymphoproliferation responses. This study presents evidence that DDA acts as an adjuvant for both coccidia antigen-specific antibody and T-cell immunity in the avian system.