Immunochemical characterization of an IgG-binding protein of Streptococcus suis (original) (raw)
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Binding Properties of Streptococcus suis for Immunoglobulin G and Other Plasma Proteins
Journal of Veterinary Medicine, Series B, 1996
Immunoglobulin G (IgG) binding proteins on the surface of Streptococcus suis could be readily detected by direct cultivation of the bacteria on nitrocellulose membranes and subsequent treatment of the membranes with human IgG. Among the 75 .I: suis isolates tested two cultures (.I: suis P43,. I: suis P143) caused a blue colouration of the membranes indicating IgG binding activities. The IgG binding proteins could be solubilized by heat treatment of the bacteria at an acid pH and also by mutanolysin treatment. Western blot analysis revealed numerous protein bands with IgG binding activities. The IgG binding proteins were also released into the culture supernatant of the bacteria. This could be detected for 51 of the 75 .I: suis using a microfiltration assay. In binding studies with '251-IgG .I: suis P43 and .I: suis PI43 but none of the other S suis isolates showed a sigruficant bindin of the protein. These two cultures additionally bound '2sI-albumin, '251-a2-macroglobulin and I2'I-fibrinogen all from humans but not '2sI-chicken IgG or I2'I-human haptoglobin 2-1. The binding profiles of the two .I: suis cultures tested indicate a close relation of these binding proteins with streptococcal protein G.
Detection of immunoglobulin-G-binding proteins in Streptococcus suis
Journal of general microbiology, 1993
This study was undertaken to search for the presence of immunoglobulin G (IgG)-binding proteins in Streptococcus suis, an important swine pathogen. Whole bacterial cells were incubated with human or pig IgG conjugated to gold particles and examined by transmission electron microscopy. Cells of some S. suis strains were labelled as were cells of the positive control strain, Staphylococcus aureus Cowan I. Binding of pig and human IgG to five different bacterial species of group D streptococci, to reference strains representing the 29 capsular types of S. suis, and to 12 S. suis capsular type 2 strains was then examined using Western blotting. All strains interacted with pig and human IgG, although the binding profiles were slightly different. A 52 kDa protein was observed in all capsular types of S. suis. This protein, absent in other group D streptococcal species, was observed in all capsular type 2 isolates originating from diseased or clinically healthy pigs, and was shown to bind ...
Journal of bacteriology, 1995
We previously reported that group D streptococci exhibited immunoglobulin G (IgG)-binding activity and that a 52-kDa IgG-binding protein was present in all Streptococcus suis strains examined (B. Serhir, R. Higgins, B. Foiry, and M. Jacques, J. Gen. Microbiol. 139:2953-2958, 1993). The objective of the present study was to purify and characterize this protein. Pig IgG were immobilized through their Fab fragments to ECH-Sepharose 4B, and the protein was purified by affinity chromatography. Electron microscopy observations of the purified material showed filamentous structures with a diameter of approximately 4 nm; these structures were not observed when the material was treated with either urea or ethanolamine. Electrophoretic and Western immunoblot analyses showed that the 52-kDa protein constituted the bulk of the recovered material. This protein was stained with either Coomassie brilliant blue or silver nitrate; it reacted with a large variety of mammalian IgG, human IgG (Fc) frag...
Identification of the site on IgG Fc for interaction with streptococci of groups A, C and G
Immunology, 1987
The interaction between living groups A, C and G streptococci and IgG Fc was studied using human IgG, IgG Fc and IgG Fc-intermediate (Fci) fragments, chemically modified human IgG and fragment D of staphylococcal protein A (SPA). Diethylpyrocarbonate modification of His or N-acetylimidazole modification of Tyr of human IgG resulted in the loss of its capacity to inhibit the binding of radiolabelled human IgG Fc to the group A streptococci types M1 and M55, and to the group C strain SC-1, indicating that the amino acids His and Tyr are involved in the binding. Lys seems not to participate in the binding of IgG to these bacteria, however, since reductive methylation of Lys did not reduce its inhibitory capacity. Fragment D of SPA also inhibited the binding of radiolabelled human IgG Fc to strains M1, M55 and SC-1. We have previously shown that these bacteria do not bind to IgG fragments consisting of only the C gamma 2 or C gamma 3 domains. On the basis of these results, and the known...
Bacterial Proteins and their Proposed Interactions with Fc or Fab Fragments of Immunoglobulins
The reactivity of Immunoglobulin Binding Proteins (IBP) to Fc and/or Fab fragments of immunoglobulins was summarized in this review. Staphylococcal protein A (SpA), Streptococcal protein G and Peptostreptococcal protein L (SpL) were the IBP reported. SpA reacted with IgG from skunk, coyote, raccoon, mule and donkey. SpG reacted almost with the entire panel of immunoglobulins and SpL binding was restricted to some immunoglobulins including raccoon, ostrich and duck. The various immunological techniques that have been used to test the binding capacity of IBP to Igs were double immunodiffusion, Enzyme-Linked Immunosorbent Assay (ELISA), SpA-affinity chromatography and immunoblot analysis. These protein-protein interactions are important because they can be used in the immunodiagnosis and in the purification of intact Igs or their fragments.
Structure of the IgG-binding regions of streptococcal protein G
The EMBO journal, 1986
The gene encoding the IgG-binding protein G from Streptococcus G148 was isolated by molecular cloning. A subclone containing a 1.5-kb insert gave a functional product in Escherichia coli. Protein analysis of affinity-purified polypeptides revealed two gene products, both smaller than protein G spontaneously released from streptococci, but with identical IgG-binding properties. The complete nucleotide sequence of the insert revealed a repeated structure probably evolved through duplications of fragments of different sizes. The deduced amino acid sequence revealed an open reading frame extending throughout the insert, terminating in a TAA stop codon. Analysis of the two gene products by N-terminal amino acid determination suggests that two different TTG codons are recognized in E. coli for initiation of translation to yield the two products. Based on these results several truncated gene constructions were expressed and analysed. The results suggest that the C-terminal part of streptoc...
Chimeric IgG-binding receptors engineered from staphylococcal protein A and streptococcal protein G
Journal of Biological Chemistry, 1988
Chimeric Fc receptors, consisting of the IgG-binding domains of both staphylococcal protein A and streptococcal protein G, were constructed. An efficient bacterial expression system was used to produce the recombinant proteins, which vary in size and number of IgG-binding domains. The purified receptors were analyzed by immunodiffusion and a competitive enzyme-linked immunosorbent assay to establish the relative binding strength to various polyclonal and monoclonal immunoglobulins from different species. The results demonstrate that protein A and protein G have complementary binding patterns and that the chimeric receptors retain the binding capacities of both the parental constituents. This suggests that these novel chimeric receptors might be versatile reagents for immunochemical assays. Staphylococcal protein A (SPA)' is used as a reagent in a variety of immunoassays (Langone, 1982), taking advantage of its affinity to the constant (Fc) part of various immunoglobulins (Forsgren and Sjoquist, 1966). Immobilized SPA has also been valuable for purification of IgG by solid phase affinity chromatography (Hjelm et al., 1972). However, SPA has limited binding to several species and subclasses of IgG, which has hampered its use. This had led to a search for other Fc-binding proteins with broader specificity. Based on studies of staphylococci and streptococci, Myhre and Kronvall(l981) proposed five different types of Fc receptors. Type I is represented by Staphylococcus aureus protein A, type I1 by group A streptococci, type I11 by human group C and G streptococci, type IV by bovine group G streptococci, and finally type V by Streptococcus zooepidemicus. All five classes of receptors show distinct binding patterns to the constant region of various classes and subclasses of mammalian IgG. A comparison between one type I11 receptor, protejn G (SPG), and protein A (Bjorck and Kronvall, 1984 and Akerstrom and Bjorck, 1986) led to the conclusion that SPG, compared to SPA, binds at least equally well and often superior to all tested polyclonal immunoglobulins and human IgG subclasses. Based on these results, it was suggested that protein G could replace protein A in immunoassays, in partic-*This investigation was supported by grants from the Swedish Board for Technical Development. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked ''advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
The Journal of Immunology
A number of group A streptococcal isolates have been compared for their nonimmune reactivity with each human IgG subclass, and rabbit, pig, or horse IgG. The results obtained demonstrate considerable heterogeneity in the expression of type II IgG-binding proteins among and within group A isolates. Extraction and analysis of type II IgG-binding proteins from selected strains demonstrate the existence of five functionally distinct IgG-binding proteins. The type IIo IgG binding protein displayed the greatest range of reactivities, binding to all four human IgG subclasses, and rabbit, pig, and horse IgG. A variant of this protein, designated type II'o, bound all four human subclasses and rabbit IgG, but failed to react with pig or horse IgG. A type IIa protein was recovered from certain group A strains which bound human IgG1, IgG2, IgG4, as well as reacting with rabbit, pig, and horse IgG. A functionally related type IIc activity that displayed all of the reactivities of the type II...