scholarly journals Putative Novel Surface-Exposed Streptococcus agalactiae Protein Frequently Expressed by the Group B Streptococcus from Zimbabwe

2009 ◽  
Vol 16 (9) ◽  
pp. 1302-1308 ◽  
Author(s):  
Rooyen T. Mavenyengwa ◽  
Johan A. Maeland ◽  
Sylvester R. Moyo
Keyword(s):  
Rabbit Antiserum ◽  
Periodate Oxidation ◽  
Cross Reactivity ◽  
Enzyme Linked Immunosorbent Assay ◽  
Protein Antigens ◽  
Group B Streptococci ◽  
Phenotypic Marker ◽  
Whole Cell ◽  
Strain Collection ◽  
Group B

ABSTRACTGroup B streptococci (GBS) express a variety of surface-exposed and strain-variable proteins which function as phenotypic markers and as antigens which are able to induce protective immunity in experimental settings. Among these proteins, the chimeric and immunologically cross-reacting alpha-like proteins are particularly important. Another protein, R3, which has been less well studied, occurred at a frequency of 21.5% in GBS from Zimbabwe and, notably, occurred in serotype V strains at a frequency of 75.9%. Working with rabbit antiserum raised against the R3 reference strain ATCC 49447 (strain 10/84; serotype V/R3) to detect the expression of the R3 protein, we recorded findings which suggested that strain 10/84 expressed a strain-variable protein antigen, in addition to R3. The antigen was detected by various enzyme-linked immunosorbent assay-based tests by using acid extract antigens or GBS whole-cell coats and by whole-cell-based Western blotting. We named the putative novel antigen the Z antigen. The Z antigen was a high-molecular-mass antigen that was susceptible to degradation by pepsin and trypsin but that was resistant tom-periodate oxidation and failed to show immunological cross-reactivity with any of a variety of other GBS protein antigens. The Z antigen was expressed by 33/121 (27.2%) of strains of a Zimbabwean GBS strain collection and by 64.2% and 72.4% of the type Ib and type V strains, respectively, and was occasionally expressed by GBS of other capsular serotypes. Thus, the putative novel GBS protein named Z showed distinct capsular antigen associations and presented as an important phenotypic marker in GBS from Zimbabwe. It may be an important antigen in GBS from larger areas of southern Africa. Its prevalence in GBS from Western countries is not known.

scholarly journals Streptococcus agalactiae Alpha-Like Protein 1 Possesses Both Cross-Reacting and Alp1-Specific Epitopes

2011 ◽  
Vol 18 (8) ◽  
pp. 1365-1370 ◽  
Author(s):  
Augusta I. Kvam ◽  
Rooyen T. Mavenyengwa ◽  
Andreas Radtke ◽  
Johan A. Maeland
Keyword(s):  
Genomic Sequence ◽  
Cross Reactivity ◽  
Antigenic Determinants ◽  
Enzyme Linked Immunosorbent Assay ◽  
Group B Streptococci ◽  
Whole Cells ◽  
Repeat Units ◽  
The Alps ◽  
Antigenic Domains ◽  
Group B

ABSTRACTMost isolates of group B streptococci (GBS) express an alpha-like protein (Alp), Cα (encoded bybca), Alp1 (also called epsilon;alp1), Alp2 (alp2), Alp3 (alp3), Alp4 (alp4), or R4/Rib (rib). These proteins are chimeras with a mosaic structure and with antigenic determinants with variable immunological cross-reactivities between the Alps, including Alp1 and Cα cross-reactivity. This study focused on antigenic domains of Alp1, studied by using rabbit antisera in immunofluorescence, Western blotting, and enzyme-linked immunosorbent assay (ELISA)-based tests and whole cells of GBS or trypsin-extracted and partially purified antigens from the strains A909 (serotype Ia/Cα, Cβ) and 335 (Ia/Alp1). Alp1 and Cα shared an antigenic determinant, Alp1/Cα common, not harbored by other Alps, probably located in the Alp1 and Cα repeat units, as these units are nearly identical in genomic sequence. An antigenic Alp1 determinant was Alp1 specific and was most likely located in the N-terminal unit of Alp1 in which an Alp1-specific primer site for PCR is also located. In addition, Alp1 possessed a domain with low immunogenicity which cross-reacted immunologically with Alp2 and Alp3, with unknown location in Alp1. Alp1 was partially degraded by trypsin during antigen extraction but with the antigenic domains preserved. The results indicate that Cα and Alp1 are immunologically related in the same manner that R4 (Rib) and Alp3 are related. The domain called Alp1 specific should be important in GBS serotyping as a surface-anchored serosubtype marker. The Alp1/Cα common determinant may be of prime interest as an immunogenic domain in a GBS vaccine.

scholarly journals Cloned alpha and beta C-protein antigens of group B streptococci elicit protective immunity.

1991 ◽  
Vol 59 (6) ◽  
pp. 2023-2028 ◽  
Author(s):  
J L Michel ◽  
L C Madoff ◽  
D E Kling ◽  
D L Kasper ◽  
F M Ausubel
Keyword(s):  
Protective Immunity ◽  
Protein Antigens ◽  
Group B Streptococci ◽  
C Protein ◽  
Group B

scholarly journals Doubly Branched Hexasaccharide Epitope on the Cell Wall Polysaccharide of Group A Streptococci Recognized by Human and Rabbit Antisera

2005 ◽  
Vol 73 (10) ◽  
pp. 6383-6389 ◽  
Author(s):  
Francis Michon ◽  
Samuel L. Moore ◽  
John Kim ◽  
Milan S. Blake ◽  
France-Isabelle Auzanneau ◽  
...  
Keyword(s):  
Cell Wall ◽  
Rabbit Antiserum ◽  
Cell Wall Polysaccharide ◽  
Group A Streptococci ◽  
Group B Streptococci ◽  
Group A ◽  
Streptococcal Polysaccharide ◽  
Synthetic Oligosaccharides ◽  
Group B ◽  
Dominant Epitope

ABSTRACT A number of epitope specificities associated with the cell wall polysaccharide antigen of group A streptococci were identified in a polyclonal rabbit antiserum induced in rabbits by whole group A streptococci and in polyclonal convalescent human antisera from children that had recovered from streptococcal A infections. The identification was achieved by using a series of synthetic oligosaccharides, glycoconjugates, and bacterial polysaccharide inhibitors to inhibit the binding of the group A helical polysaccharide to the polyclonal antisera. The exclusively dominant epitope expressed in the convalescent human antisera was the doubly branched extended helical hexasaccharide with the structure α-l-Rhap(1→2)[β-d-GlcpNAc(1→3)]α-l-Rhap(1→3)α-l-Rhap(1→2)[β-d-GlcpNAc(1→3)]α-l-Rhap. The hexasaccharide epitope also bound with the highest immunoreactivity to the rabbit antiserum. In contrast, the human antisera did not show significant binding to the singly branched pentasaccharide with the structure α-l-Rhap(1→2)α-l-Rhap(1→3)α-l-Rhap(1→2)[β-d-GlcpNAc(1→3)]α-l-Rhap or the branched trisaccharide α-l-Rhap(1→2)[β-d-GlcpNAc(1→3)]α-l-Rhap, although both these haptens bound significantly to the same rabbit antiserum, albeit with less immunoreactivity than the hexasaccharide. Inhibition studies using streptococcal group A and B rabbit antisera and the inhibitors indicated above also suggested that the group A carbohydrate, unlike the group B streptococcal polysaccharide, does not contain the disaccharide α-l-Rhap(1→2)α-l-Rhap motif at its nonreducing chain terminus, stressing the importance of mapping the determinant specificities of these two important streptococcal subcapsular group polysaccharides to fully understand the serological relationships between group A and group B streptococci.

scholarly journals Characterization of the Specific Interaction between Sialoadhesin and Sialylated Campylobacter jejuni Lipooligosaccharides

2010 ◽  
Vol 78 (7) ◽  
pp. 3237-3246 ◽  
Author(s):  
Astrid P. Heikema ◽  
Mathijs P. Bergman ◽  
Hannah Richards ◽  
Paul R. Crocker ◽  
Michel Gilbert ◽  
...  
Keyword(s):  
Sialic Acid ◽  
Campylobacter Jejuni ◽  
Cho Cells ◽  
Molecular Mimicry ◽  
Specific Interaction ◽  
Enzyme Linked Immunosorbent Assay ◽  
Whole Cell ◽  
Cell Enzyme ◽  
Strain Collection ◽  
Preferential Binding

ABSTRACT In Campylobacter jejuni-induced Guillain-Barré syndrome (GBS), molecular mimicry between C. jejuni lipooligosaccharide (LOS) and host gangliosides leads to the production of cross-reactive antibodies directed against the peripheral nerves of the host. Currently, the presence of surface exposed sialylated LOS in C. jejuni is the single known bacterial pathogenesis factor associated with the development of GBS. Using a unique, well-characterized strain collection, we demonstrate that GBS-associated C. jejuni strains bind preferentially to sialoadhesin (Sn, Siglec-1, or CD169), a sialic acid receptor found on a subset of macrophages. In addition, using a whole-cell enzyme-linked immunosorbent assay (ELISA), C. jejuni strains with sialylated LOS bound exclusively to soluble Sn. Mass spectrometry revealed that binding was sialic acid-linkage specific with a preference for α(2,3)-linked sialic acid attached to the terminal galactose of the LOS chain as seen in the gangliosides GD1a, GM1b, and GM3. This molecular interaction was also related to functional consequences as a GBS-associated C. jejuni strain that bound Sn in a whole-cell ELISA adhered to surface-expressed Sn of Sn-transfected CHO cells but was unable to adhere to wild-type CHO cells. Moreover, a sialic acid-negative mutant of the same C. jejuni strain was unable to bind Sn-transfected CHO cells. This is the first report of the preferential binding of GBS-associated C. jejuni strains to the Sn immune receptor (P = 0.014). Moreover, because this binding is dependent on sialylated LOS, the main pathogenic factor in GBS progression, the present findings bring us closer to unraveling the mechanisms that lead to formation of cross-reactive antibodies in GBS disease.

scholarly journals Antibodies against Streptococcus agalactiae Proteins cα and R4 in Sera from Pregnant Women from Norway and Zimbabwe

2001 ◽  
Vol 8 (6) ◽  
pp. 1110-1114 ◽  
Author(s):  
Sylvester R. Moyo ◽  
Johan A. Maeland ◽  
James Mudzori
Keyword(s):  
Pregnant Women ◽  
Human Serum ◽  
Gel Filtration ◽  
The Other ◽  
Enzyme Linked Immunosorbent Assay ◽  
Protein Antigens ◽  
Childbearing Age ◽  
Serum Antibodies ◽  
Group B Streptococci ◽  
Antibody Levels

ABSTRACT Group B streptococci (GBS) express strain-variable and surface-localized proteins, which are important serotype markers and targets of protective antibodies. These include the cαand R4 proteins, one or the other of which is expressed by approximately 75% of clinical GBS isolates. These proteins have been considered vaccine candidates. In this study, the cα and R4 proteins were extracted by trypsin digestion of GBS and purified by sequential precipitation with trichloroacetic acid and ammonium sulfate followed by gel filtration chromatography. The proteins were used as antigens in an indirect enzyme-linked immunosorbent assay (ELISA) to measure the levels of cα- and R4-reactive antibodies in sera from pregnant women from Norway (n = 100) and from Zimbabwe (n = 124). Antibody levels in the Norwegian group of women were significantly higher than in the Zimbabwean group, and a higher proportion of the Norwegian women contained appreciable levels of antibodies against both proteins. The antibodies traversed the placental barrier. With individual sera, a significant correlation between the anti-cα and anti-R4 antibody levels was observed and each of the two protein antigens effectively competed for human serum antibodies both against itself and against the other antigen. Inhibition ELISA results demonstrated specificity for each of the proteins of immune antibodies raised in rabbits. These results demonstrate that (i) the majority of women of childbearing age have antibodies against cα and R4, (ii) the levels of these antibodies differ among pregnant women in different parts of the world, and (iii) the normal human serum antibodies may target a common cα and R4 protein site, whereas immune antibodies targeted a different site(s) specific for each protein.

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