Viral Protein Structure
Five viral proteins designated VP1, VP2, VP3, VP4 and VP5 have been recognised:
- VP1 plays a key role in the encapsidation of the virus particle.
- VP2 encodes the major antigenic determinants of the virus, including epitopes that are important in virus neutralisation.
- VP3 is a group specific antigen that is recognised by non-neutralising antibodies. VP3 acts as an intermediary, interacting with both VP1 and VP2, and the formation of VP1-VP3 complexes is likely to be an important step in the morphogenesis of IBDV particles.
- VP4 is a minor and non-structural polypeptide.
- VP5 likely has a regulatory function.