title: Novel rabies virus-neutralizing epitope recognized by human monoclonal antibody: fine mapping and escape mutant analysis.
abstract: Anti-rabies virus immunoglobulin combined with rabies vaccine protects humans from lethal rabies infections. For cost and safety reasons, replacement of the human or equine polyclonal immunoglobulin is advocated, and the use of rabies virus-specific monoclonal antibodies (MAbs) is recommended. We produced two previously described potent rabies virus-neutralizing human MAbs, CR57 and CRJB, in human PER.C6 cells. The two MAbs competed for binding to rabies virus glycoprotein. Using CR57 and a set of 15-mer overlapping peptides covering the glycoprotein ectodomain, a neutralization domain was identified between amino acids (aa) 218 and 240. The minimal binding region was identified as KLCGVL (aa 226 to 231), with key residues K-CGV- identified by alanine replacement scanning. The critical binding region of this novel nonconformational rabies virus epitope is highly conserved within rabies viruses of genotype 1. Subsequently, we generated six rabies virus variants escaping neutralization by CR57 and six variants escaping CRJB. The CR57 escape mutants were only partially covered by CRJB, and all CRJB-resistant variants completely escaped neutralization by CR57. Without exception, the CR57-resistant variants showed a mutation at key residues within the defined minimal binding region, while the CRJB escape viruses showed a single mutation distant from the CR57 epitope (N182D) combined with mutations in the CR57 epitope. The competition between CR57 and CRJB, the in vitro escape profile, and the apparent overlap between the recognized epitopes argues against including both CR57 and CRJB in a MAb cocktail aimed at replacing classical immunoglobulin preparations.
authors.affiliation: Crucell Holland BV, Archimedesweg 4, P.O. Box 20482301, CA Leiden, The Netherlands.
authors.forename: Wilfred E
authors.initials: WE
authors.lastname: Marissen
authors.forename: R Arjen
authors.initials: RA
authors.lastname: Kramer
authors.forename: Amy
authors.initials: A
authors.lastname: Rice
authors.forename: William C
authors.initials: WC
authors.lastname: Weldon
authors.forename: Michael
authors.initials: M
authors.lastname: Niezgoda
authors.forename: Milosz
authors.initials: M
authors.lastname: Faber
authors.forename: Jerry W
authors.initials: JW
authors.lastname: Slootstra
authors.forename: Rob H
authors.initials: RH
authors.lastname: Meloen
authors.forename: Marieke
authors.initials: M
authors.lastname: Clijsters-van der Horst
authors.forename: Therese J
authors.initials: TJ
authors.lastname: Visser
authors.forename: Mandy
authors.initials: M
authors.lastname: Jongeneelen
authors.forename: Sandra
authors.initials: S
authors.lastname: Thijsse
authors.forename: Mark
authors.initials: M
authors.lastname: Throsby
authors.forename: John
authors.initials: J
authors.lastname: de Kruif
authors.forename: Charles E
authors.initials: CE
authors.lastname: Rupprecht
authors.forename: Bernhard
authors.initials: B
authors.lastname: Dietzschold
authors.forename: Jaap
authors.initials: J
authors.lastname: Goudsmit
authors.forename: Alexander B H
authors.initials: AB
authors.lastname: Bakker
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D045744:Cell Line, Tumor; D017124:Conserved Sequence; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D051379:Mice; D008969:Molecular Sequence Data; D009447:Neuroblastoma; D009500:Neutralization Tests; D011818:Rabies / Q000276:immunology*; D011820:Rabies virus / Q000235:genetics* / Q000276:immunology*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
chemical_list: D000911:Antibodies, Monoclonal; D007074:Immunoglobulin G