THE MAJOR ANTIGENIC PROTEIN OF INFECTIOUS BURSAL DISEASE VIRUS, VP2, IS AN APOPTOTIC INDUCER

Infectious bursal disease virus (IBDV) is the causative agent of an ec onomically important poultry disease, Vaccinia virus recombinants expr essing the IBDV mature structural capsid proteins VP2 and VP3 were gen erated by using vectors for inducible gene expression. Characterizatio n of these recombinant viruses demonstrated that expression of VP2 lea ds to induction of apoptosis in a variety of mammalian cell lines, Tra nsfection of cell cultures with a expression vector containing the VP2 coding region under the control of the immediate-early promoter-enhan cer region of human cytomegalovirus also triggers programmed cell deat h, The apoptotic effect of VP2 is efficiently counteracted by coexpres sion of the proto-oncogene bcl-2. The results presented demonstrate th at VP2 is a bona fide apoptotic inducer. Evaluation of the significanc e of this finding for the virus life cycle must await further research .