The effect of infectious bursal disease virus infection on local and systemic antibody responses following infection of 3-week-old broiler chickens.

Broiler chickens infected at 3 weeks of age with infectious bursal disease virus (IBDV) were given Brucella abortus (BA) or sheep red blood cell (SRBC) antigens before, during, and after the acute phase of the infection. Gland of Harder (GH) extracts and serum samples were used to assay local and systemic antibody titer to each antigen 7 days after antigen was administered. Antibody titers to both BA and SRBC antigens were lower (P less than 0.05) in GH extracts and serum of IBDV-infected broilers than uninfected controls. The responses to BA, a thymus-independent antigen, took longer to become depressed than the responses to SRBC, a thymus-dependent antigen. The depression of antibody titers following IBDV inoculation suggests compromise of both local and systemic immune function, a finding of importance to the broiler industry.