Antibodies to human papillomavirus type-16 in human sera as revealed by the use of prokaryotically expressed viral gene products.

Open reading frames of human papillomaviruses were expressed in Escherichia coli as beta-galactosidase fusion proteins. These bacterially derived papillomaviral gene products were used to examine sera from 67 women (63 healthy subjects, 4 patients with genital carcinoma) for antibodies to papillomavirus type-16 antigens (E1, E2, E4, E5, E6, E7, L1, L2) and the L2 proteins of HPV-6b and HPV-18 by Western-blot analysis. The serologic data were compared with cytological findings classified according to Papanicolaou and with nucleic acid hybridization data from cervical smears of the same individuals. Twenty-three of the normal individuals showed antibodies exclusively directed against L2 gene products; whereas in the sera from the four genital cancer patients, antibodies to the early gene products E4 and/or E7 could be detected. In one case these antibodies were found to be combined with antibodies to L2 of HPV-16 and -18 and in another case with those to E1 and E2 of HPV-16. In none of the sera examined could antibodies to L1, E5 or E6 be identified. Three of the antibody positive normal women were found to be also positive for HPV-16/18 DNA, while all of the 40 seronegative women were HPV-16/18 DNA negative. These data indicate that serology may be a valuable means to study the epidemiology of genital human papillomavirus infection.