Bindings of plasma proteins to streptococci of serological group L with special reference to their immunoglobulin G Fc-receptor activity

Abstract

Of 33 streptococcal cultures belonging to serological group L, all bound human immunoglobulin (Ig) G, fibrinogen, and fibronectin; 32 bound bovine IgG; 31 bound alpha 2-macroglobulin; 5 bound albumin; and none bound either haptoglobin or IgA. The binding sites for IgG could be isolated from the L streptococci by trypsinization and purified by affinity chromatography on human IgG-Sepharose. The purified Fc receptors reacted with IgG subclasses 1, 2, 3, 4 of humans, 1 and 2 of bovines, ovines, and caprines as well as a, b, c, and T of equines. They had a molecular mass of approximately 49,000 Da. Thus, the Fc receptors from L streptococci corresponded to type III Fc receptors of Streptococcus dysgalactiae.

Further Studies on Immunoglobulin G‐ and Albumin‐Binding Properties of Streptococci of Serological Group L

“…However, the IgG-and albumin-binding results of this and previous studies (LAMMLER, 1988;LAMMLER et al, 1988;LAMMLER and FREDE, 1989) also show similar, if not identical, binding activities for both S. dysguluctiue and group L streptococci.…”

“…In inhibition studies with IgG and albumin preparations from humans and various animals, selected group L streptococci displayed comparable binding activities to those of streptococci of serological groups C and G. The IgG-binding site of a group L streptococcus corresponded to type I11 Fc-receptors of groups C and G streptococci, as described by MYHRE and KRONVALL, (1981), and the albumin-binding site of a group L streptococcus corresponded to type b albumin receptors of group G streptococci, as described by WIDEBACK et al (1983), LAMMLER et al (1988), and LAMMLER (1988).…”

“…Radio-iodination of immunoglobulin G and albumin, both from humans (Sigma, Deisenhofen, Germany), with Iz5I was performed using the chloramin T method (HUNTER and GREENWOOD, 1962). The binding assays were performed as described by LAMMLER et al (1988). For this, approximately 2 x 10' streptococci, adjusted photometrically, were reacted with 20 pl (2 x 10'-4 x lo4 cpm) radiolabelled proteins and incubated for 1 h at room temperature.…”

Characteristic Properties of Streptococci of Serological Group L

“…Serotyping the group L streptococci by staphyloccoccal co-agglutination or with Mprotein-specific antisera prepared in chickens prevented unspecific reactions of IgG Fc-receptors in group L streptococcal antigen preparations with IgG. The binding sites for IgG on the group L streptococcal surface were described by LAMMLER et al (1988). However, streptococcal IgG Fc-receptors are well known not to interact with chicken IgG (BJORCK and AKERSTROM, 1990).…”

Binding Properties of Streptococcus suis for Immunoglobulin G and Other Plasma Proteins

“…Comparable IgG binding proteins were described for S. &qa/uctiue, S. canis, and streptococci of the serological group L, all isolated from animals ( LAMMLER et al, 1988;LAMMLER and FREDF,, 1989;SIPPEL and LAMMLER, 1995) and more recently also for the important swine pathogen S. suis (SERHIR et al., 1993, 1995). According to SERHIR et al (1993) IgG binding to .I suzs appears to be related to a common protein with an approximate molecular mass of 52 kDa.…”