Topographical and conformational epitopes of bovine papillomavirus type 1 defined by monoclonal antibodies.

Monoclonal antibodies (MAbs) were generated against sodium dodecyl sulfate-disrupted bovine papillomavirus type 1 (BPV-1). When screened by enzyme-linked immunosorbent assay (ELISA) on intact and disrupted BPV-1, -2, and deer papillomavirus, three patterns of reactivity were defined: reactivity only with intact virus, with both intact and disrupted virus, and only with disrupted virus. On the basis of ELISA results, the topographical location and requirement for conformation for immunoreactivity of epitopes was defined as external conformational, external linear, and internal linear. Cross-reactivity of MAbs with other papillomavirus types was analyzed by immunofluorescence on warts from different species. Type-specific, BPV-1 and/or -2 cross-reactive, broadly cross-reactive, and genus-specific MAbs were identified. MAb reactivity with structural polypeptides of BPV-1 was analyzed by Western blot. MAbs reactive with epitopes defined as conformational by ELISA did not react in Western blot. All MAbs reactive in Western blot reacted with the major capsid protein (MCP) [55 kilodalton (kDa)], demonstrating that the MCP carries both type-specific and cross-reactive epitopes. Most MAbs reactive with the MCP were cross-reactive with structural polypeptides of 48 and 96 kDa, demonstrating the immunologic relatedness of these three polypeptides.