A monoclonal antibody‐based agar gel precipitin test for antigenic assessment of infectious bursal disease viruses

Five monoclonal antibodies (MAbs) directed at different neutralization epitopes of infectious bursal disease virus (IBDV) precipitated IBDV antigens in double immunodiffusion. Based on the positive or negative reaction of some of the MAbs in agar gel precipitin tests (AGPT), four different antigenic species of IBDV could be discerned. Although the antigen-capture enzyme-linked immunosorbent assays (AC-ELISA) were more sensitive than AGPTs for differentiating IBDV types, use of the MAbs in AGPT did offer a useful and accessible technique for differentiating wild type IBDV directly from infected tissues taken in the field.