title: Detection of human papillomavirus type 18 E7 oncoprotein in cervical smears: a feasibility study.
abstract: Persistent infections by high-risk human papillomaviruses (HPVs) are the main etiological factor for cervical cancer, and expression of HPV E7 oncoproteins was suggested to be a potential marker for tumor progression. The objective of this study was to generate new reagents for the detection of the HPV18 E7 oncoprotein in cervical smears. Rabbit monoclonal antibodies against recombinant E7 protein of HPV type 18 (HPV18) were generated and characterized using Western blotting, epitope mapping, indirect immunofluorescence, and immunohistochemistry. One clone specifically recognizing HPV18 E7 was used for the development of a sandwich enzyme-linked immunosorbent assay (ELISA). The assay was validated using recombinant E7 proteins of various HPV types and lysates from E7-positive cervical carcinoma cells. A total of 14 HPV18 DNA-positive cervical swab specimens and 24 HPV DNA-negative-control specimens were used for the determination of E7 protein levels by the newly established sandwich ELISA. On the basis of the average absorbance values obtained from all 24 negative controls, a cutoff above which a clinical sample can be judged E7 positive was established. Significant E7 signals 6- to 30-fold over background were found in 7 out of 14 abnormal HPV18 DNA-positive cervical smear specimens. This feasibility study demonstrates for the first time that HPV18 E7 oncoprotein can be detected in cervical smears.
authors.affiliation: Institute for Biomedical Aging Research of the Austrian Academy of Sciences, Innsbruck, Austria.
authors.forename: Daniela
authors.initials: D
authors.lastname: Ehehalt
authors.forename: Barbara
authors.initials: B
authors.lastname: Lener
authors.forename: Haymo
authors.initials: H
authors.lastname: Pircher
authors.forename: Kerstin
authors.initials: K
authors.lastname: Dreier
authors.forename: Heiko
authors.initials: H
authors.lastname: Pfister
authors.forename: Andreas M
authors.initials: AM
authors.lastname: Kaufmann
authors.forename: Sergio
authors.initials: S
authors.lastname: Frangini
authors.forename: Sigrun
authors.initials: S
authors.lastname: Ressler
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Müller-Holzner
authors.forename: Markus
authors.initials: M
authors.lastname: Schmitt
authors.forename: Daniela
authors.initials: D
authors.lastname: Höfler
authors.forename: Ursula
authors.initials: U
authors.lastname: Rostek
authors.forename: Andreas
authors.initials: A
authors.lastname: Kaiser
authors.forename: Andreas
authors.initials: A
authors.lastname: Widschwendter
authors.forename: Werner
authors.initials: W
authors.lastname: Zwerschke
authors.forename: Pidder
authors.initials: P
authors.lastname: Jansen-Dürr
mesh_terms: D000911:Antibodies, Monoclonal; D055088:Early Detection of Cancer / Q000379:methods*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D052161:Human papillomavirus 18 / Q000276:immunology / Q000302:isolation & purification*; D006801:Humans; D050725:Papillomavirus E7 Proteins / Q000032:analysis* / Q000276:immunology; D030361:Papillomavirus Infections / Q000175:diagnosis*; D014621:Vagina / Q000821:virology*; D014626:Vaginal Smears; D014773:Virology / Q000379:methods*
chemical_list: D000911:Antibodies, Monoclonal; D050725:Papillomavirus E7 Proteins