scholarly journals Protein rib: a novel group B streptococcal cell surface protein that confers protective immunity and is expressed by most strains causing invasive infections.

1993 ◽  
Vol 177 (6) ◽  
pp. 1593-1603 ◽  
Author(s):  
M Stålhammar-Carlemalm ◽  
L Stenberg ◽  
G Lindahl
Keyword(s):  
Cell Surface ◽  
Protective Immunity ◽  
Group B Streptococcus ◽  
Rabbit Antiserum ◽  
Surface Protein ◽  
Amino Acid Sequences ◽  
Cell Surface Protein ◽  
Type Iii ◽  
Invasive Infections ◽  
Group B

The group B Streptococcus, an important cause of invasive infections in the neonate, is classified into four major serotypes (Ia, Ib, II, and III) based on the structure of the polysaccharide capsule. Since the capsule is a known virulence factor, it has been extensively studied, in particular in type III strains, which cause the majority of invasive infections. Two cell surface proteins, alpha and beta, have also been studied in detail since they confer protective immunity, but these proteins are usually not expressed by type III strains. We describe here a cell surface protein, designated protein Rib (resistance to proteases, immunity, group B), that confers protective immunity and is expressed by most strains of type III. Protein Rib was first identified as a distinct 95-kD protein in extracts of a type III strain, and was purified to homogeneity from that strain. Rabbit antiserum to protein Rib was used to demonstrate that it is expressed on the cell surface of 31 out of 33 type III strains, but only on 1 out of 25 strains representing the other three serotypes. Mouse protection tests showed that antiserum to protein Rib protects against lethal infection with three different strains expressing this antigen, including a strain representing a recently identified high virulence type III clone. Protein Rib is immunologically unrelated to the alpha and beta proteins, but shares several features with the alpha protein. Most importantly, the NH2-terminal amino acid sequences of the Rib and alpha proteins are identical at 6 out of 12 positions. In addition, both protein Rib and the alpha protein are relatively resistant to trypsin (and Rib is also resistant to pepsin) and both proteins vary greatly in size between different clinical isolates. Finally, both protein Rib and the alpha protein exhibit a regular ladderlike pattern in immunoblotting experiments, which may reflect a repetitive structure. Taken together, these data suggest that the Rib and alpha proteins are members of a family of proteins with related structure and function. Since protein Rib confers protective immunity, it may be valuable for the development of a protein vaccine against the group B Streptococcus, an encapsulated bacterium.

scholarly journals Protection from Group B Streptococcal Infection in Neonatal Mice by Maternal Immunization with Recombinant Sip Protein

2002 ◽  
Vol 70 (9) ◽  
pp. 4897-4901 ◽  
Author(s):  
Denis Martin ◽  
Stéphane Rioux ◽  
Edith Gagnon ◽  
Martine Boyer ◽  
Josée Hamel ◽  
...  
Keyword(s):  
Protective Immunity ◽  
Group B Streptococcus ◽  
Surface Protein ◽  
Neonatal Infection ◽  
Active Immunization ◽  
Infection Model ◽  
Lethal Challenge ◽  
Specific Antibodies ◽  
Pregnant Mice ◽  
Group B

ABSTRACT The protective potential of antibodies directed against group B streptococcus (GBS) Sip surface protein was determined by using the mouse neonatal infection model. Rabbit Sip-specific antibodies administered passively to pregnant mice protected their pups against a GBS lethal challenge. In addition, active immunization with purified recombinant Sip protein of female CD-1 mice induced the production of specific antibodies that also confer protection to the newborn pups against GBS strains of serotypes Ia/c, Ib, II, III, and V. These data confirm that Sip-specific antibodies can cross the placenta and conferred protective immunity against GBS infections.

Structural determination and serology of the native polysaccharide antigen of type-III group B Streptococcus

1980 ◽  
Vol 58 (2) ◽  
pp. 112-120 ◽  
Author(s):  
Harold J. Jennings ◽  
Karl-Gunnar Rosell ◽  
Dennis L. Kasper
Keyword(s):  
Sialic Acid ◽  
Group B Streptococcus ◽  
Rabbit Antiserum ◽  
Ph Control ◽  
Molar Ratio ◽  
Polysaccharide Antigen ◽  
Type Iii ◽  
Group B ◽  
Unit Formula ◽  
Ph Controlled

The native polysaccharide antigen isolated from type-III group B Streptococcus contains D-galactose (Gal), D-glucose (Glc), 2-acetamido-2-deoxy-D-glucose (GlcNAc), and sialic acid (NeuNAc) in the molar ratio of 2:1:1:1 and its structure can be represented by the following repeating unit:[Formula: see text]By cleavage of all the labile sialic acid end groups the incomplete type-III antigen is obtained which is structurally identical to the S. pneumoniae type-14 polysaccharide. Thus, the native type-III polysaccharide is serologically distinct from the incomplete type-III antigen by virtue of the former having determinants terminating in sialic acid and the latter in β-D-galactopyranose units. None of these latter determinants could be detected in streptococcal organisms grown under pH-controlled conditions (pH 7.0) or in rabbit antiserum made to these pH-controlled organisms. However, in antisera produced in rabbits to the same organisms grown without pH control (Lancefield procedures), antibodies to both types of determinant could be detected. This can be attributed to the removal of some of the masking sialic acid residues from the cell-associated native polysaccharide by degradative procedures which occur during these latter conditions.

scholarly journals Identification and Characterization of a Novel Heme-Associated Cell Surface Protein Made by Streptococcus pyogenes

2002 ◽  
Vol 70 (8) ◽  
pp. 4494-4500 ◽  
Author(s):  
Benfang Lei ◽  
Laura M. Smoot ◽  
Heather M. Menning ◽  
Jovanka M. Voyich ◽  
Subbarao V. Kala ◽  
...  
Keyword(s):  
Recombinant Protein ◽  
Cell Surface ◽  
Surface Protein ◽  
Cell Surface Protein ◽  
Gene Encoding ◽  
Invasive Infections ◽  
Group A

ABSTRACT Analysis of the genome sequence of a serotype M1 group A Streptococcus (GAS) strain identified a gene encoding a previously undescribed putative cell surface protein. The gene was cloned from a serotype M1 strain, and the recombinant protein was overexpressed in Escherichia coli and purified to homogeneity. The purified protein was associated with heme in a 1:1 stoichiometry. This streptococcal heme-associated protein, designated Shp, was produced in vitro by GAS, located on the bacterial cell surface, and accessible to specific antibody raised against the purified recombinant protein. Mice inoculated subcutaneously with GAS and humans with invasive infections and pharyngitis caused by GAS seroconverted to Shp, indicating that Shp was produced in vivo. The blood of mice actively immunized with Shp had significantly higher bactericidal activity than the blood of unimmunized mice. The shp gene was cotranscribed with eight contiguous genes, including homologues of an ABC transporter involved in iron uptake in gram-negative bacteria. Our results indicate that Shp is a novel cell surface heme-associated protein.

scholarly journals Molecular Dissection of the secA2 Locus of Group B Streptococcus Reveals that Glycosylation of the Srr1 LPXTG Protein Is Required for Full Virulence

2009 ◽  
Vol 191 (13) ◽  
pp. 4195-4206 ◽  
Author(s):  
Michel-Yves Mistou ◽  
Shaynoor Dramsi ◽  
Sara Brega ◽  
Claire Poyart ◽  
Patrick Trieu-Cuot
Keyword(s):  
Cell Surface ◽  
Surface Display ◽  
Group B Streptococcus ◽  
Surface Protein ◽  
Cell Surface Display ◽  
Variable Number ◽  
Bacterial Adherence ◽  
Neonatal Rat ◽  
Genes Encoding ◽  
Group B

ABSTRACT In streptococci, the secA2 locus includes genes encoding the following: (i) the accessory Sec components (SecA2, SecY2, and at least three accessory secretion proteins), (ii) two essential glycosyltranferases (GTs) (GtfA and GtfB), (iii) a variable number of dispensable additional GTs, and (iv) a secreted serine-rich LPXTG protein which is glycosylated in the cytoplasm and transported to the cell surface by this accessory Sec system. The secA2 locus of Streptococcus agalactiae strain NEM316 is structurally related to those found in other streptococci and encodes the serine-rich surface protein Srr1. We demonstrated that expression of Srr1 but not that of the SecA2 components and the associated GTs is regulated by the standalone transcriptional regulator Rga. Srr1 is synthesized as a glycosylated precursor, secreted by the SecA2 system, and anchored to the cell wall by the housekeeping sortase A. Srr1 was localized preferentially at the old poles. GtfA and/or GtfB, but not the six additional GTs, is essential for the production of Srr1. These GTs are involved in the attachment of GlcNac and sialic acid to Srr1. Full glycosylation of Srr1 is associated with the cell surface display of a protein that is more resistant to proteolytic attack. Srr1 contributes to bacterial adherence to human epithelial cell lines and virulence in a neonatal rat model. The extent of Srr1 glycosylation by GtfC to -H modulates bacterial adherence and virulence.

Growth of group B streptococci in human serum leads to increased cell surface sialic acid and decreased activation of the alternative complement pathway

1994 ◽  
Vol 40 (2) ◽  
pp. 99-105 ◽  
Author(s):  
Mark W. Platt ◽  
Norberto Correa Jr. ◽  
Carolyn Mold
Keyword(s):  
Sialic Acid ◽  
Cell Surface ◽  
Human Serum ◽  
Group B Streptococcus ◽  
Group B Streptococci ◽  
Sialic Acid Content ◽  
Bacterial Surface ◽  
Type Iii ◽  
Alternative Complement ◽  
Group B

Group B streptococcus type III is a major cause of neonatal death. The terminal sialic acid moiety of the group B streptococcus type specific capsule has been shown to be an important virulence factor. We demonstrate here that bacteria grown in human serum have increased cell surface sialic acid content compared with cells grown in common laboratory media. This sialic acid was removed by incubation with neuraminidase, showing that it was on the bacterial surface. Serum-dependent sialylation was dependent on metabolic activity, as the addition of chloramphenicol reduced the amount of added sialic acid by more than 90%. Probing the cell surface with an antibody specific for group B streptococcus type III capsular sialic acid showed an increase in antibody binding after growth in human serum. This effect could be lowered by incubating serum-grown cells in neuraminidase prior to antibody exposure. A group B streptococcus mutant that when grown in laboratory media lacks cell surface sialic acid showed significant cell surface sialic acid when grown in human serum. This increase was associated with a significantly decreased ability to bind C3 and hence activate the alternative complement pathway.Key words: group B streptococcus, capsule, human serum.

scholarly journals Emergence of Invasive Serotype Ib Sequence Type 10 Group B Streptococcus Disease in Chinese Infants Is Driven by a Tetracycline-Sensitive Clone

2021 ◽  
Vol 11 ◽  
Author(s):  
Li Zhang ◽  
Wen-Juan Kang ◽  
Lei Zhu ◽  
Li-Jun Xu ◽  
Chao Guo ◽  
...  
Keyword(s):  
Late Onset ◽  
Medical Center ◽  
Group B Streptococcus ◽  
Surface Protein ◽  
Sequence Type ◽  
Genetic Lineage ◽  
Clinical Complications ◽  
Invasive Infections ◽  
Severe Infections ◽  
Group B

BackgroundGroup B streptococcus (GBS) is a leading cause of serious infections in infants. The extensive use of tetracycline has led to the selection of specific resistant and infectious GBS clones. The sequence type (ST) 10 GBS strain, causing invasive infections in infants, is becoming prevalent in China. We aimed to understand the clinical and microbiological characteristics of this GBS strain.MethodsWe conducted a retrospective study on infants with invasive GBS disease from the largest women’s and children’s medical center in Shanxi and collected data between January 2017 and October 2020. GBS isolates were analyzed by capsule serotyping, genotyping, antibiotic resistance, and surface protein genes.ResultsAll ST10 isolates belonged to serotype Ib; type Ib/ST10 strains were responsible for 66.7% (14/21, P < 0.05) of infant invasive GBS infections during the period and all resulted in late-onset (LOD) and late LOD disease (14/14). Infants with type Ib/ST10 GBS disease had significantly higher rates of meningitis (9/14, 64.3%, p < 0.05) and clinical complications (5/14, 35.7%, p < 0.05). The Ib/ST10 GBS isolates had limited genetic diversity, clustered in the CC10/bca/PI-1 + PI-2a genetic lineage, showed resistance to erythromycin, lincomycin, and fluoroquinolones and sensitivity to tetracycline, and possessed genes ermT, ermB, and amino acid changes in gyrA and parC.ConclusionsThe probable clonal expansion can result in severe infections in infants and ongoing emergence of multi-drug resistant isolates. Continued monitoring for type Ib/ST10 GBS infections is warranted.

Immunogold and immunoblot studies on a cell surface protein found in primary mesenchyme cells and in the cortical secretory vesicles of the sea urchin egg

1987 ◽  
Vol 45 ◽  
pp. 832-833
Author(s):  
G.L. Decker ◽  
M.C. Valdizan
Keyword(s):  
Cell Surface ◽  
Sea Urchin ◽  
Surface Protein ◽  
Egg Cell ◽  
Secretory Vesicles ◽  
Cell Surface Protein ◽  
Surface Complexes ◽  
Mesenchyme Cells ◽  
Lowicryl K4m ◽  
Primary Mesenchyme Cells

A monoclonal antibody designated MAb 1223 has been used to show that primary mesenchyme cells of the sea urchin embryo express a 130-kDa cell surface protein that may be directly involved in Ca2+ uptake required for growth of skeletal spicules. Other studies from this laboratory have shown that the 1223 antigen, although in relatively low abundance, is also expressed on the cell surfaces of unfertilized eggs and on the majority of blastomeres formed prior to differentiation of the primary mesenchyme cells.We have studied the distribution of 1223 antigen in S. purpuratus eggs and embryos and in isolated egg cell surface complexes that contain the cortical secretory vesicles. Specimens were fixed in 1.0% paraformaldehyde and 1.0% glutaraldehyde and embedded in Lowicryl K4M as previously reported. Colloidal gold (8nm diameter) was prepared by the method of Mulpfordt.

Sign in / Sign up

Export Citation Format

Share Document