Detection of antibodies to a linear epitope on the major coat protein (L1) of human papillomavirus type-16 (HPV-16) in sera from patients with cervical intraepithelial neoplasia and children.

Antibodies to the major (L1) coat protein of human papillomavirus type 16 (HPV-16) in sera from patients with cervical intra-epithelial neoplasia (CIN) have been investigated by means of recombinant proteins and synthetic peptides. When L1-HPV-16 fusion proteins were used in immunoblot assays, no antibody reactivity was found in sera from 52 patients with CIN or from 21 unrelated children. Amino-acid sequence analyses indicated that L1-HPV-16 amino acids 473 to 492 may contain an HPV-16 type-restricted epitope since the greatest diversity occurs in this region. In the ELISA, seropositivity to peptides 473 to 492 was more common among CIN patients whose biopsies contained HPV-16 DNA (91%, 21 of 23) than among their children (24%, 5 of 21; p less than 0.001) or other CIN patients with HPV-16 DNA-negative biopsies (66%, 19 of 29; p less than 0.05), but was unrelated to the severity of the CIN lesion. Antibodies to L1-HPV-16 peptide 473 to 492 among seropositive CIN patients cross-reacted with the analogous L1-HPV-33, but not with the L1-HPV-6b peptide, and were predominantly IgM. In contrast, antibodies which recognized a less variable region of L1-HPV-16 (amino acids 279 to 293) showed no association with HPV-16 DNA status. Seropositivity to the L1-HPV-6b (amino acids 473-492) was less frequent (33%) among CIN patients and unassociated with HPV-16 DNA status (p greater than 0.1); however 51% (37 of 72) of patients with genital warts had antibodies to this peptide.