Identification of Immunogenic Regions of the Major Coat Protein of Human Papillomavirus Type 16 that Contain Type-restricted Epitopes

Abstract

SUMMARYWe have identified regions of the major capsid protein, L1, of the human papillomavirus (HPV) type 16 , that are recognized by five monoclonal antibodies (MAbs) raised to a bacterial fusion protein containing residues 172 to 375 of HPV-16 L1. All five MAbs recognized HPV-16-infected tissue sections by immunohistochemistry, but not sections infected with HPV-la (cutaneous warts), HPV-6b or -11 (genital warts). MAbs 3D1, 5A4 and 1D6 also recognized HPV-2-infected sections (cutaneous warts); MAb 8C4 recognized only sections containing HPV-16. Four MAbs (8C4, 3D1, 1D6 and 5A4) recognized a synthetic peptide corresponding to residues 269 to 284 of HPV-16 L1; within this region a minimum antibody binding site was identified, a tripeptide 276 to 278. However the complete epitope appears to extend beyond these residues and beyond HPV-16 L1 (269 to 284). The fifth MAb, 1C6, recognized bacterial fusion proteins containing HPV-6b L1, -16 L1 or -18 L1 using immunoblots, yet appeared HPV-16-specific when tested on infected tissue sections. This MAb recognized five amino acids within a different region of HPV-16 L1 (residues 299 to 313). INTRODUCTIONPapillomaviruses infect avian, reptile and mammalian hosts, causing epithelial proliferation (Sundberg, 1987). Humans are susceptible to at least 58 types of papillomaviruses. Human papillomavirus (HPV) types 16, 18, 31, 33 and 52 which cause genital infections have been associated with high grade cervical intraepitheliat neoptasia lesions and invasive carcinoma, and other genital HPV types (e.g. HPV-6b and HPV-11) are more commonly associated with benign conditions such as genital warts (McCance, 1986). If the relationship between certain types of HPV and pre-invasive and invasive cancer of the cervix is proven to be of a causal rather than casual nature, rapid and accurate diagnosis of the type of HPV infection is likely to be important in the clinical management of patients with these diseases. At present, diagnosis of the exact type of HPV infection relies upon nucleic acid hybridization techniques, which are time-consuming and expensive when compared to immunohistochemical or serological methods of viral identification. A serological test for exposure to high risk HPV types would thus provide an easier method of identifying patients who may be at greatest risk of developing a malignant disease.The major capsid protein (L 1) of papillomaviruses, which is the most abundant virus-encoded protein, is highly conserved between different types, with amino acid homologies as high as 80~ existing between some L1 proteins from different papillomavirus types. As a consequence

Identification of seroreactive regions of the human papillomavirus type 16 proteins E4, E6, E7 and L1

“…Additional support was provided by the fact that identical results were obtained with different antisera prepared in individual rabbits (in the case of E4) or even with sera derived from different species (rabbit and mouse, in the case of E7-221). Epitope 221 of the E7 protein (Table 1) has also been found by Tindle et al (1990), and Cason et al (1989) described an epitope within the L1-830 region. Moreover, synthetic peptides derived from the E7 epitope 107 and from the E4 epitope were found to react with a number of human sera and experiments by Dillner et al (1990) demonstrated the presence of human antibodies directed against L1 peptides overlapping with antigenic regions L1-809 (three amino acids overlap), L1-830 (12 amino acids overlap) and L1-842 (complete overlap; see Table 1) (Dillner et al, 1990).…”

Mapping of linear B cell epitopes on capsid proteins of bovine papillomavirus: identification of three external type-restricted epitopes

“…Pepscans of the entire BPV-1 (Chen et al, 1982), BPV-2 (Potter & Meinke, 1985), human PV type 16 (HPV-16;Seedorf et al, 1985) and HPV-18 (Cole & Danos, 1987) L1 and L2 amino acid sequences were produced on polyethylene pins by f-moc chemistry (Cambridge Research Biochemicals;Geysen et al, 1987) as 15-met peptides with a five amino acid overlap (amino acids 1 to 15, 11 to 25 etc.). Positive control peptides included HPV-16 L1 amino acids 269 to 284 (ENVPDDLYIKGSGSTA), which is recognized by monoclonal antibody (MAb) 8C4 (Cason et al, 1989), and PLAQ, which is recognized by a MAb supplied with the Pepscan kit, as well as a negative control peptide (GLAQ) were used to check the fidelity of peptide syntheses.…”

Detection of E5 oncoprotein in human papillomavirus type 16-positive cervical scrapes using antibodies raised to synthetic peptides

“…The reactivity of each antiserum with both partial and full-length HPV-16 E5 peptides was determined by enzyme immunoassays (EIA) as previously described (Cason et al, 1989 * Subjective assessment by eye of intensity of staining by 4-chlorol-naphthol was as follows: + + + +, very strong through to -, no staining observed.…”