Mapping of linear epitopes on fibre knob of human adenovirus serotype 5

Linear antigenic epitopes on the Ad5 fibre knob (FK5) were characterised with fibre- and virion-specific antisera, using 15-mer overlapping peptides covering the knob of the fibre. They were compared with epitopes on the Ad2 fibre knob (FK2) domain. The stronger reactive FK5 epitopes were represented by peptides P3 (amino acids (aa A419–L433)), P6 (aa S449–E463), P7 (aa I459–L473), P12 (aa G509–N523), P14 (aa P529–G543) and P16 (aa A549–Y563). P3 spans the B β-strand and the left portion of the C β-strand, P6 and P7 the D β-strand and the adjacent parts of the CD and DE loops, P12, P14 and P16 the G, H and I β strands and the adjacent parts of the loops, respectively. The stronger reactive epitopes on FK2 were located in P2 (aa P409–L423), P6 (aa T449–Q463), P8 (aa E469–G483), P13 (aa Q519–T533) and P16 (aa S549–K563). The positions of FK5 and FK2 derived peptides, representing epitopes, are either identical or overlapping or adjacent, as determined by amino acid sequence alignment. Antisera obtained against several longer peptides showed virus neutralising capacity, indicating neutralising epitopes in these peptides.