Epitomics: IgG-epitome decoding of E6, E7 and L1 proteins from oncogenic human papillomavirus type 58

To enable rational multi-epitope vaccine and diagnostic antigen design, it is imperative to delineate complete IgG-epitome of the protein. Here, we describe results of IgG-epitome decoding of three proteins from high-risk (HR-) oncogenic human papillomavirus type 58 (HPV58). To reveal their entire epitomes, employing peptide biosynthetic approach, 30 precise linear B-cell epitopes (BCEs) were mapped on E6, E7 and L1 proteins using rabbits antisera to the respective recombinant proteins. Using sequence alignment based on BCE minimal motif, the specificity and conservativeness of each mapped BCE were delineated mainly among known HR-HPVs, including finding 3 broadly antibody cross-reactive BCEs of L1 that each covers almost all HR-HPVs. Western blots revealed that 13 of the 18 BCEs within L1-epitome were recognized by murine antisera to HPV58 virus-like particles, suggesting that these are antibody accessible BCEs. Also, a highly conserved epitope (YGD/XTL) of E6 was found to exist only in known common HR-HPVs, which could be used as the first peptide reference marker for judging HR-HPVs. Altogether, this study provides systemic and exhaustive information on linear BCEs of HR-HPV58 that will facilitate development of novel multi-epitope diagnostic reagents/chips for testing viral antibodies and ‘universal’ preventive HPV peptide vaccine based on L1 conserved BCEs.