Premium
On the Interaction between β 2 ‐Microglobulin and Group A Streptococci
Author(s) -
BJÖRCK L.,
MIÖRNER H.,
KÜHNEMUND O.,
KRONVALL G.,
SUNDLER R.
Publication year - 1984
Publication title -
scandinavian journal of immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.934
H-Index - 88
eISSN - 1365-3083
pISSN - 0300-9475
DOI - 10.1111/j.1365-3083.1984.tb00979.x
Subject(s) - lipoteichoic acid , beta (programming language) , streptococcus pyogenes , beta 2 microglobulin , streptococcus , group a , plasma protein binding , chemistry , myeloma protein , antigen , microbiology and biotechnology , bacteria , biology , biochemistry , antibody , staphylococcus aureus , immunology , genetics , medicine , computer science , programming language
β 2 ‐microglobulin (β 2 m) was found to interact with many group A streptococcal strains. The interaction appeared to require multipoint attachment, since monomeric β 2 m in solution showed no binding, whereas both β 2 m monomers bound to liposomes, and β 2 m in aggregates showed affinity for the bacteria. Aggregated HLA antigens (‐A, ‐B and ‐C) and aggregated β 2 m exhibited the same binding patterns when tested in binding experiments with various group A streplococcal strains. Furthermore, β 2 m aggregates in excess completely blocked the binding of aggregated HLA antigens, thereby demonstrating that β 2 m is able to interact with streptococcal surface structures also when it is part of the HLA antigen complex. M protein‐positive group A streptococcal strains bound significantly more β 2 m than M protein‐negative variants of these strains. Purified M 12 protein partly inhibited the binding of radiolabelled β 2 ‐m aggregates to whole streptococci, and in gel filtration and affinity chromatography experiments, the M 12 protein interacted with β 2 m. These various data suggest that the interaction between β 2 m and group A streptococci could be mediated by M protein. Lipoteichoic acid (LTA) is a constituent of the streptococcal cell wall that has been reported to form complexes with M protein at the bacterial cell surface. However, LTA did not influence the interaction between β 2 m and streptococci, suggesting that the binding of β 2 m to streptococcal M protein represents a pure protein‐protein interaction. In vivo such an interaction could be established between infecting streptococci and host cells. Among 45 strains of different M types large differences in β 2 m binding were recorded, whereas among 60 strains of the classical nephritogenic M types 12 and 49, all were highly β 2 m‐reactive, which points towards a role for β 2 m in streptococcal pathogenicity.