Identification of the site on IgG Fc for interaction with streptococci of groups A, C and G

Department of Rheumatology, University Hospital of Lund, Sweden.
Immunology (Impact Factor: 3.8). 01/1988; 62(4):523-7.
Source: PubMed


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 relative positions in space of the His and Tyr residues on IgG Fc, it is speculated whether streptococci with IgG Fc receptors, like SPA and rheumatoid factors, interact with IgG in the interface between the C gamma 2 and C gamma 3 domains and involve His 435 and one or more of Tyr 436, His 433 and His 310. The similarities in binding sites on IgG for RFs and these bacterial Fc binding proteins suggest structural similarities between them that may be relevant to the production of rheumatoid factors in rheumatoid arthritis.

Download full-text


Available from: Francis Nardella, May 23, 2015
  • Source
    • "Spa binding is mediated through an exposed histidine residue at position 435 in human IgG (Deisenhofer, 1981). It has been proposed that DEPC interferes with the binding of Spa to histidine-435 in human IgG (Schroder et al., 1987). Our results indicate that DEPC prevents the direct binding of Spa to anti-LukS-PV. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Enzyme-linked immunosorbent assay (ELISA) and Western blotting are common techniques used to detect and quantify proteins in Staphylococcus aureus culture supernatants, such as Panton-Valentine leukocidin (PVL). However, protein A (Spa) secreted by most S. aureus strains may interfere with these assays by binding to the capturing and detecting antibodies. Here, we have shown that the addition of diethylpyrocarbonate (DEPC) inhibits the binding of Spa to rabbit anti-PVL used as the capturing antibody in ELISA. In Western blotting, the presence of DEPC prevented the binding of detecting antibody to Spa. These modified ELISA and Western blot techniques should prove useful for detecting and quantifying proteins in S. aureus culture supernatants.
    Full-text · Article · Mar 2010 · Journal of immunological methods
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The binding site of immunoglobulin G (IgG) to herpes simplex virus (HSV) type 1-induced Fc receptor was investigated using human IgG Fc intermediate (Fc(i)) fragments, fragment D of staphylococcal protein A (SPA) and chemically modified human IgG. Human IgG Fc(i) fragment composed of one Cgamma2 and two Cgamma3 domains, bound strongly to HSV-1-infected cells. Fragment D, a monovalent subunit of SPA, inhibited the binding of radiolabelled human IgG Fc fragments to the HSV Fc receptor. Reductively methylated human IgG reacted equally well to HSV-infected cells, as did chemically unmodified IgG in contrast to N-acetylimidazole-modified and diethylpyrocarbonate-modifed human IgG, which were unreactive. These results suggest a similar binding site on human IgG for SPA and the HSV-1 Fc receptor with involvement of the amino acid residues Tyr and His but not Lys. The similarities of binding sites on the IgG molecule for the HSV-1 Fc receptor and rheumatoid factors (RF) may be important for understanding the mechanism of RF production in rheumatoid arthritis or other disease states.
    Full-text · Article · Feb 1989 · Immunology
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A receptor binding the Fc region of equine immunoglobulin G (IgG) has been isolated from a heat-extracted preparation of a clinical isolate of Streptococcus zooepidemicus. This Fc receptor has a Mr of 45 x 10(3) and was occasionally seen as an apparent trimer of Mr 130 x 10(3). Antibodies prepared in horses against the receptor could be adsorbed to and eluted from whole live bacteria, confirming the surface location of this protein. Another 11 isolates of S. zooepidemicus from horses with pneumonia, abscesses or endometritis were tested for Fc-receptor activity. Although the Mr of the Fc receptors varied among isolates, their antigenicity was conserved. Thus, the Fc receptor is an attractive candidate for application in the diagnosis of, or protection against, infections with S. zooepidemicus.
    Preview · Article · Mar 1989 · Journal of Medical Microbiology
Show more