title: Isolation of sequences from a random-sequence expression library that mimic viral epitopes.
abstract: We describe the use of random peptide sequences for the mapping of antigenic determinants. An oligonucleotide with a completely degenerate sequence of 17 or 23 nucleotides was inserted into a bacterial expression vector. This resulted in an expression library producing random hexa- or octapeptides attached to a beta-galactosidase hybrid protein. Mimotopes, or antigenic sequences that mimic an epitope, were selected by immunoscreening of colonies with monoclonal antibodies, which were specific for antigenic sites on the spike protein of the coronavirus transmissible gastroenteritis virus. We report one mimotope for antigenic site II, eight for site III and one for site IV. The site III and site IV mimotopes were closely similar to the corresponding linear epitopes, localized previously in the amino acid sequence of the S protein. An alignment of the site II mimotope and the sequence of the S protein around Trp97, which is substituted in escape mutants, suggests that this mimotope mimics a conformational epitope located around residues 97-103. Applications of mimotopes to epitope mapping, serodiagnosis and vaccine development are discussed.
authors.affiliation: Institute of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht, Netherlands.
authors.forename: J A
authors.initials: JA
authors.lastname: Lenstra
authors.forename: J H
authors.initials: JH
authors.lastname: Erkens
authors.forename: J G
authors.initials: JG
authors.lastname: Langeveld
authors.forename: W P
authors.initials: WP
authors.lastname: Posthumus
authors.forename: R H
authors.initials: RH
authors.lastname: Meloen
authors.forename: F
authors.initials: F
authors.lastname: Gebauer
authors.forename: I
authors.initials: I
authors.lastname: Correa
authors.forename: L
authors.initials: L
authors.lastname: Enjuanes
authors.forename: K K
authors.initials: KK
authors.lastname: Stanley
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000954:Antigens, Surface / Q000276:immunology; D000956:Antigens, Viral / Q000276:immunology*; D001483:Base Sequence; D015153:Blotting, Western; D003429:Cross Reactions / Q000276:immunology; D000939:Epitopes / Q000276:immunology*; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression; D015723:Gene Library; D008969:Molecular Sequence Data; D015345:Oligonucleotide Probes; D009842:Oligopeptides / Q000276:immunology / Q000302:isolation & purification*; D010957:Plasmids; D005760:Transmissible gastroenteritis virus / Q000276:immunology*; D014764:Viral Proteins / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D000956:Antigens, Viral; D000939:Epitopes; D015345:Oligonucleotide Probes; D009842:Oligopeptides; D014764:Viral Proteins; C064484:spike protein S, Transmissible gastroenteritis virus