Immunosuppression induced by infectious bursal disease virus.

Immunosuppression caused by infectious bursal disease virus (IBDV) is of major interest because of the widespread occurrence of the infection in commercial chickens. Infection with IBDV at an early age significantly compromises the humoral and local immune responses of chickens. The cellular immune response is also compromised by apparently to a lesser extent and for a short period. The immunosuppression seems to be a result of direct effect (lysis) of B cells or their precursors. Other mechanisms of immunosuppression have been suggested, notably the development of suppressor cells.