Induction of protective immunity in chickens orally immunized with inactivated infectious bursal disease virus

The present studies were undertaken to examine the effects of oral administration of formalin-inactivated infectious bursal disease virus (IBDV) on the immune responses of chickens. Inactivated IBDV was suspended in phosphate-buffered saline containing sodium bicarbonate. This form of antigen, when administered by oral instillation, induced a serum antibody response against IBDV in chickens and these chickens were protected from subsequent viral challenge. The immunoglobulin class of IBDV-specific antibodies in serum was found to be IgG when determined by enzyme-linked immunosorbent assay. Cholera toxin, which has been reported to have potent mucosal adjuvant properties in mammals, did not enhance the serum antibody response. Oral followed by parenteral administrations of antigen induced an enhanced antibody response in chickens.