Recombinant proteins encoded by the E2, E7, L1, and L2 open reading frames (ORF) of human papillomavirus (HPV) types 6b, 16, and 18 were used in Western blot assays to detect serum IgG antibodies in women attending a sexually transmitted diseases clinic (n = 92) and in hospitalized children (n = 81). Antibodies to late gene products (L1 or L2 ORF) were more common than antibodies to early gene products (E2 or E7), both in the adults and the children; overall, the antibody prevalences in the children and the sexually active adults were not significantly different. Human sera with high titers of antibodies to the HPV16 E7 recombinant protein immunoprecipitated the genuine HPV16 E7 protein from the cervical carcinoma cell line CaSki. As an independent measure of HPV infection, the polymerase chain reaction was used to detect HPV6b and HPV16 in oral mucosal scrapings from adults (n = 35) and preschool children (n = 21). In adults, HPV6b and HPV16 DNA were detected in 17% and 23% of oral mucosal samples, respectively. In preschool children, HPV6b and HPV16 DNA were found in 24% and 19% of oral samples, respectively.

Recombinant proteins encoded by the human papillomavirus type 6b (HPV6b) Li open reading frame react with sera from patients with condylomata acuminata and also react with rabbit antiserum raised against sodium dodecyl sulfate-disrupted bovine papillomavirus type 1 (BPVI) virions. To map the immunoreactive epitopes, a series of procaryotic expression plasmids was made which contained a nested set of 3' to 5' deletions in the HPV6b Li open reading frame. The deleted plasmids expressed a set of carboxy to amino terminus truncated fusion proteins. Regions containing the immunoreactive epitopes were mapped by determining which of the deleted fusion proteins retained reactivity with sera in Western immunoblot assays. The coding sequence for a human antibody-reactive linear epitope mapped between HPV6b nucleotide coordinates 7045 and 7087, and the rabbit anti-BPV1-reactive epitope coding sequence mapped between coordinates 6377 and 6454. Synthetic peptides derived from the epitope mapping were reacted with sera in enzyme-linked immunosorbent assay. Human sera reacted with synthetic peptide QSQAITCQKPTPEKEKPDPYK (HPV6b Li amino acids 417 through 437). Rabbit anti-BPVi and rabbit antisera raised against HPV6b and HPV16 Li recombinant proteins reacted with the synthetic peptide DGDMVDTGFGAMNFADLQTNKSDVPIDI (HPV6b Li amino acids 193 through 220). Human sera which reacted with HPV6b Li fusion proteins cross-reacted with an HPVlI Li fusion protein but did not react with fusion proteins encoded by HPVla, HPV16, or HPV18. Rabbit anti-BPV1 reacted with Li fusion proteins encoded by all of these HPV types. In contrast to the type-common (rabbit anti-BPVI-reactive) epitope, the human antibody-reactive epitope appears to be relatively HPV type specific.

We have previously reported that the most common human serum immunoglobulin G antibody reactivities to human papillomavirus type 16 and type 18 (HPV16 and HPV18)-encoded proteins are directed against the minor capsid proteins (HPV16 L2 and HPV18 L2) and to the E7 protein of HPV16 (S. A

Human papillomavirus type 1 (HPV1) virions, both as intact virion particles (IVP) and as detergentdenatured virions (DDV), were used to prepare polyclonal antisera and monoclonal antibodies (MAbs) in BALB/c mice. Anti-IVP antiserum contained type-specific HPV1 L2-reactive antibodies and no detectable HPV1 Ll-reactive antibodies. Anti-IVP MAbs recognized a linear epitope between L2 amino acids 102 and 108 (PIDVVDP). Anti-DDV antiserum contained type-specific HPV1 Ll-reactive and HPV1 L2-reactive antibodies. An anti-DDV MAb recognized a linear epitope between Li amino acids 127 and 133 (AENPTNY). HPVla Liand L2-encoded polypeptides expressed in Saccharomyces cerevisiae and by in vitro translation were equivalent in size to the major and minor virion capsid proteins, respectively.