Antibodies Against the Human Papillomavirus Type 16 Early Proteins in Human Sera: Correlation of Anti-E7 Reactivity With Cervical Cancer

Abstract

By Western blot technique, 519 samples of human sera were tested for the presence of antibodies to the human papillomavirus (HPV) type 16 proteins E4 and E7 that had been expressed in Escherichia coli as fusion proteins. Sera were obtained from patients attending the University hospitals for reasons unrelated to HPV infections (controls), from patients with HPV-associated lesions, as well as from patients suffering from cervical cancer. Within the control population, 18.1% of them had antibodies that reacted with the E4 protein, and 3.9% of them had antibodies that reacted with the E7 protein. No sex-specific difference in the antibody prevalence was observed. The highest proportion of anti-E4 antibody-positive individuals (40.7%) was observed in the age group between 11 and 20 years. The frequency of anti-E4-positive sera was threefold higher in patients with HPV-associated genital lesions than that in age-matched controls. Antibodies against the HPV16 E7 protein were found 14 times more frequently in patients with cervical cancer, compared with age- and sex-matched controls (P less than .00001). From these data, we concluded that anti-E4 antibodies may be correlated with virus replication and that anti-E7 antibodies may represent a marker for cervical cancer development.

Comparison of ELISA and Western blotting for human papillomavirus type 16 E7 antibody determination

“…1 in WB. This serum also reacted with an MS2 HPV-16 E4 fusion protein (Jochmus-Kudielka et al, 1989) in WB and this reactivity was not influenced by treatment with any of the HPV-16 E7 peptides. As expected, the absorbed serum lost its reactivity with the 16/E7-2 peptide in ELISA.…”

“…In the past few years increasing efforts have been made to develop serological tests capable of proving HPV infection. In these tests, three sources of antigens have been utilized: (i) intact or disrupted HPV virions extracted either from HPVinduced lesions (Pfister & zur Hausen, 1978;Baird, 1983;Dillner et al, 1989a;Steele & Gallimore, 1990;Anisimov/t et al, 1990) or from virus-infected xenografts in nude mice (Christensen & Kreider, 1990), (ii) genetically engineered HPV proteins, usually in the form of bacterial fusion proteins (Jenison et al, 1988(Jenison et al, , 1989Jochmus-Kudielka et al, 1989) or expressed as part of a capsid protein of genetically modified phage fd (Mfiller et al, 1990) and (iii) synthetic peptides derived from known sequences of different HPV DNA open reading frames (ORFs) (Cason et al, 1989;Dillner, 1990;Dillner et al, 1989bDillner et al, , 1990Such~.nkov/~ et al, 1990;Miiller et al, 1990).…”

“…In WB experiments, lysates of genetically engineered Escherichia coli expressing HPV-16 E7 and HPV-16 E4 fusion proteins were used (Jochmus-Kudielka et al, 1989). They were derived from the expression vectors pEX 8 mer-HPV-16 E7 and pEX 12 mer-HPV-16 E4 constructed by Seedorf et al (1987).…”

“…They contain the whole HPV-16 E7 ORF [nucleotides (nt) 585 to 855] and HPV-16 E40RF (nt 3399 to 3617), respectively, fused to the DNA sequence encoding the first 100 amino acids of the bacteriophage MS2 polymerase. Preparation of the expressed fusion protein from bacterial extracts and WB analysis of sera which had been preabsorbed with lysates of the parental bacteria, were performed according to Jochmus-Kudielka et al (1989); for visualization of the antigen-antibody reaction peroxidase-labelled pig antihuman IgG (SwaHu, Sevac) was used. As a control antigen a protein comprising the first 100 amino acids of the MS2 polymerase was employed (Jochmus-Kudielka et al, 1989).…”

Specificity of human cytotoxic T lymphocytes induced by a human papillomavirus type 16 E7-derived peptide.

“…rejection of tumours expressing either antigen (Chen et al, 1991(Chen et al, , 1992. In CIN and cervical cancer patients, however, the cellular immune response against HPV is obviously not strong enough to inhibit tumour growth, although E6 and E7 induce antibody reactivity and T cell proliferation, and hence are also immunogenic in humans (Jochmus-Kudielka et al, 1989 ;Mu$ ller et al, 1992 ;Kadish et al, 1994 ;de Gruijl et al, 1996).…”