Anti-idiotypic antibody specific for an infectious bursal disease virus-neutralizing monoclonal antibody does not interfere with the virus infection

Infectious bursal disease virus (IBDV) capsid protein, VP2, contains a hypervariable domain that is recognized by virus-neutralizing antibodies. The virus-neutralizing epitope is highly conformation-dependent and the domain is speculated to be involved in the virus-target cell interaction. In this study, a polyclonal anti-idiotypic antibody (anti-id) was generated by the sequential immunization of a rabbit with a virus-neutralizing monoclonal antibody GI-11 which recognizes the VP2 hypervariable domain. Although the anti-id, which mimics the conformational epitope in the VP2 hypervariable domain, was expected to inhibit the virus infection, the anti-id did not interfere with either the virus binding or the infection to the target cell.