title: Emergence of a new virulent clone within the electrophoretic type 5 complex of serogroup B meningococci in Norway.
abstract: An increase in B:15:P1.12 meningococci among isolates from patients with Neisseria meningitidis infection in Norway in recent years led to further characterization of such strains. Between 1987 and 1992, B:15:P1.12 strains constituted 9.8% (24 strains) of B:15 isolates. The B:15:P1.12 strains belonged to the electrophoretic type 5 (ET-5) complex, but 17 (71%) strains were a new clone (ET-5c) not found elsewhere in the world. All but one strain of ET-5c were responsible for a localized outbreak of systemic meningococcal disease in western Norway. A novel monoclonal antibody (202,G-12), developed against the unknown variable region 2 on the class 1 protein of one of these strains, bound to 19 of the 15:P1.12 strains, 4 strains bound the subtype P1.13 reference monoclonal antibody MN24H10.75, and the remaining strain showed no reaction. Sequencing of porA genes demonstrated a series of nine threonine residues in the deduced variable region 2 of the latter strain, while four and five threonine residues were found in the corresponding regions of strains reacting with the monoclonal antibodies 202,G-12 and MN24H10.75, respectively. Epitope mapping with synthetic peptides showed that 202,G-12 bound to a sequence of 11 amino acids which included the four threonine residues specific for subtype P1.13a. Immunoglobulin G antibodies against the P1.7,16 subtype protein, induced in volunteers after vaccination with the Norwegian meningococcal vaccine, did not cross-react on immunoblots with the subtype protein of clone ET-5c. Thus, postvaccination class 1 protein antibodies, assumed to be protective, may not be effective against infection with the new clone.
authors.affiliation: Department of Vaccine, National Institute of Public Health, Oslo, Norway.
authors.forename: E
authors.initials: E
authors.lastname: Wedege
authors.forename: J
authors.initials: J
authors.lastname: Kolberg
authors.forename: A
authors.initials: A
authors.lastname: Delvig
authors.forename: E A
authors.initials: EA
authors.lastname: Høiby
authors.forename: E
authors.initials: E
authors.lastname: Holten
authors.forename: E
authors.initials: E
authors.lastname: Rosenqvist
authors.forename: D A
authors.initials: DA
authors.lastname: Caugant
mesh_terms: D000293:Adolescent; D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal / Q000276:immunology; D001426:Bacterial Proteins / Q000276:immunology*; D001770:Blood Bactericidal Activity; D002999:Clone Cells; D004586:Electrophoresis; D018604:Epitope Mapping; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D008969:Molecular Sequence Data; D009345:Neisseria meningitidis / Q000145:classification* / Q000276:immunology / Q000472:pathogenicity*; D016870:Neisseriaceae Infections / Q000453:epidemiology / Q000276:immunology*; D009664:Norway / Q000453:epidemiology; D016036:Seroepidemiologic Studies; D012703:Serotyping; D014774:Virulence
chemical_list: D000911:Antibodies, Monoclonal; D001426:Bacterial Proteins; D007074:Immunoglobulin G