Mapping of epitopes on the fiber knobs of human adenovirus serotypes 8 and 15

In order to obtain information on the linear antigenic epitopes on fiber knobs of adenovirus serotypes 8 (Ad8) and 15 (Ad15) of subgenus D, the binding of polyclonal virus- and fiber-specific rabbit antibodies to overlapping peptides covering the fiber knob was studied. The main antigenic epitopes of the fiber knob of Ad8 (FK8) were represented by the peptides P4 amino acids (aa) 213-227], P6 (aa 233-247), P11 (aa 283-297), P13 (aa 303-317) and P15 (aa 316-325); the peptides P1 (aa 183-197), P8 (aa 253-267), P10 (aa 273-287) and P23 (aa 340-349) were moderately reactive. The peptides P4, P6, P11, P13 and P15 span the beta strands C, D, G and H, parts of the CD and DG loops and the complete GH loop of the fiber knob. The main epitopes of the fiber knob of Ad15 (FK15) were represented by peptides P5 (aa 198-212), P10 (aa 223-237), P12 (aa 233-247), P13 (aa 238-252), P26 (aa 303-317), P29 (aa 318-332) and P32 (aa 333-347), spanning the beta strands B, D, G, H and I, partly strand C, the CD loop, parts of the AB and DG loops, the GH and HI loops and the N-terminal part of the IJ loop. The amino acid sequence alignment showed that the location of the linear FK8 and FK15 epitopes was found to be overlapping to a major extent. Two serotype-specific epitopes were determined on FK15, represented by P10 and P13.