Localization of surface immunogenic protein on group B streptococcus.
The localization and accessibility of the group B streptococcus (GBS) surface immunogenic protein (Sip) at the surface of intact GBS cells were studied by flow cytometric assay and immunogold electron microscopy. Antibodies present in pooled sera collected from mice after immunization with purified recombinant Sip efficiently recognized native Sip at the surfaces of the different GBS strains tested, which included representatives of all nine serotypes. Examination of GBS cells by immunogold electron microscopy revealed that the Sip-specific antibodies attached preferentially to polar sites and the septal region. This result confirmed that Sip is exposed at the intact-cell surface, but it also suggests that its distribution is restricted to certain regions of the cell.
Rioux
S
S
Unité de Recherche en Vaccinologie, Centre Hospitalier Universitaire de Québec et Université Laval, Ste-Foy, Québec, Canada G1V 4G2. Stephanie.Rioux@crchul.ulaval.ca
Martin
D
D
Ackermann
H W
HW
Dumont
J
J
Hamel
J
J
Brodeur
B R
BR
D000818:Animals; D000942:Antigens, Bacterial / Q000032:analysis* / Q000276:immunology; D000954:Antigens, Surface / Q000032:analysis* / Q000276:immunology; D002417:Cattle; D018985:Epitopes, B-Lymphocyte / Q000276:immunology; D006801:Humans; D051379:Mice; D013292:Streptococcus agalactiae / Q000276:immunology*
D000942:Antigens, Bacterial; D000954:Antigens, Surface; D018985:Epitopes, B-Lymphocyte; C414463:SIP protein, Streptococcus group B