Virus enhancement following infection with antibody-coated infectious bursal disease virus (IBDV) in chickens.

A novel concept of vaccination, employing virus-antibody complex has been reported for the control of infectious bursal disease in chickens. A comparison of virus replication, serum neutralizing antibody response and pathogenicity in chickens inoculated with the antibody coated virus, prepared by mixing virus and antibody in different ratios (1:1, 1:0.1, 1: 0.01) and virus alone without antibody, has been made. Antibody coated virus (when mixed in certain crucial ratios) replicated to a higher magnitude in the target organ, caused more severe pathogenesis but induced a primary serum neutralizing antibody response almost comparable. The results may have important implications in understanding of pathogenesis and development of control strategies against infectious bursal disease virus, specially employing immune complex vaccine.