title: Molecular analysis of group B protective surface protein, a new cell surface protective antigen of group B streptococci.
abstract: Group B streptococci (GBS) express various surface antigens designated c, R, and X antigens. A new R-like surface protein from Streptococcus agalactiae strain Compton R has been identified by using a polyclonal antiserum raised against the R protein fraction of this strain to screen a lambda Zap library. DNA sequence analysis of positive clones allowed the prediction of the primary structure of a 105-kDa protein designated BPS protein (group B protective surface protein) that exhibited typical features of streptococcal surface proteins such as a signal sequence and a membrane anchor region but did not show significant similarity with other known sequences. Immunogold electron microscopy using a BPS-specific antiserum confirmed the surface location of BPS protein on S. agalactiae strain Compton R. Anti-BPS antibodies did not cross-react with R1 and R4 proteins expressed by two variant type III GBS strains but reacted with the parental streptococcal strain in Western blot and immunoprecipitation analyses. Separate R3 and BPS immunoprecipitation bands were observed when a cell extract of strain Compton R was tested with an antiserum against Compton R previously cross-absorbed to remove R4 antibodies. Immunization of mice with recombinant BPS protein by the subcutaneous route produced an efficient antigen-specific response, and immunized animals survived challenge with a lethal dose of a virulent strain. Therefore, BPS protein represents a new R-like protective antigen of GBS.
authors.affiliation: Department of Microbial Pathogenesis and Vaccine Research, GBF--German Research Centre for Biotechnology, 38124 Braunschweig, Germany.
authors.forename: Sezgin
authors.initials: S
authors.lastname: Erdogan
authors.forename: Peter K
authors.initials: PK
authors.lastname: Fagan
authors.forename: Susanne R
authors.initials: SR
authors.lastname: Talay
authors.forename: Manfred
authors.initials: M
authors.lastname: Rohde
authors.forename: Patricia
authors.initials: P
authors.lastname: Ferrieri
authors.forename: Aurea E
authors.initials: AE
authors.lastname: Flores
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Guzmán
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Walker
authors.forename: Gursharan S
authors.initials: GS
authors.lastname: Chhatwal
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology; D000942:Antigens, Bacterial / Q000096:biosynthesis / Q000235:genetics* / Q000276:immunology / Q000302:isolation & purification; D000954:Antigens, Surface / Q000096:biosynthesis / Q000235:genetics* / Q000276:immunology / Q000302:isolation & purification; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification; D001483:Base Sequence; D015153:Blotting, Western; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000032:analysis; D008565:Membrane Proteins / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification; D051379:Mice; D008969:Molecular Sequence Data; D010434:Pepsin A; D011817:Rabbits; D017422:Sequence Analysis, DNA; D013290:Streptococcal Infections / Q000382:microbiology* / Q000517:prevention & control; D013292:Streptococcus agalactiae / Q000235:genetics* / Q000276:immunology; D014357:Trypsin; D014611:Vaccination
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D000954:Antigens, Surface; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D008565:Membrane Proteins; C447143:group B protective surface protein, S agalactiae; D014357:Trypsin; D010434:Pepsin A