Immune responses in chickens against Eimeria tenella sporozoite antigen.

Two-day old broiler chicks were subcutaneously immunized with Eimeria tenella sporozoite antigen (25 microg per chick) with or without adjuvants on 2 and 18 days of age and the effect of induced immunity was determined by challenging the chickens with 10(4) homologous sporulated oocysts at 32 days of age. Chicks immunized with sporozoite antigen emulsified in Freund's Complete Adjuvant (FCA) showed protection in terms of oocyst production, mortality and mean lesion scores. Antigen emulsified in FCA produced significant cell mediated immune responses (as assessed by lymphocyte migration inhibition test) from 12 to 30 days post-immunization. Antibody responses as assessed by enzyme linked immunosorbent assay were significant from 12 days postimmunization when the antigen was administered with or without adjuvants by subcutaneous route.