Selection of polyclonal antibodies to the N terminus of bean yellow mosaic potyvirus coat protein by induction of tolerance with monoclonal antibody

Polyclonal antisera to potyviruses contain virus-specific as well as cross-reacting antibodies. The virus-specific antibodies are directed to the surface-located, N-terminal region of the coat protein, whereas cross-reacting antibodies are produced against multiple epitopes within the core region of the coat protein (minus N and C termini), which displays extensive sequence homology among distinct potyviruses. In the present study, immunological tolerance was induced in mice against the cross-reactive central core region of bean yellow mosaic virus (BYMV) using a rat monoclonal antibody (mAb) to the L3T4 molecule (the mouse equivalent of CD4). Generation of specific antisera reactive to the N terminus of BYMV was attained in tolerized mice by secondary immunization with whole viral coat protein from BYMV. This approach appears to be ideally suited to potyviruses where a two-third of the coat protein molecule contains immunogenic epitopes which can result in cross-reacting antibodies.