SCANNING THE STRUCTURE AND ANTIGENICITY OF HPV-16 E6 AND E7 ONCOPROTEINS USING ANTIPEPTIDE ANTIBODIES

The structure and antigenicity of the HPV-16 E6 and E7 oncoproteins wa s studied using a set of antisera against overlapping synthetic peptid es. We report that antigenic, mobile regions of the native proteins, a s defined by reactivity with antipepide antisera, occur at the N-termi ni of both E6 and E7 proteins, corresponding to regions of known or su spected protein-protein interactions. The putative zinc finger domains were consistently non-reactive, despite computer predictions of relat ively high antigenicity, suggesting that the proposed zinc finger regi ons are held in stable secondary structures that the peptides were not able to mimic. In E6, the linker region between the two zinc fingers was antigenic, indicating that the two zinc finger structures might be able to articulate relative to one another by a flexible linker regio n. The highly antigenic N-terminal region of HPV-16 E7 was also found to be antigenic in E7 of both HPV-11 and HPV-18, indicating that the E 7 proteins of different HPV types have similar antigenic structures. T he identification of antigenic regions of the E6 and E7 proteins shoul d be therefore be useful in the design of site-directed antibodies aga inst E6 and E7 for numerous HPV types.