title: beta 2-Microglobulin is bound to streptococcal M protein.
abstract: The presence of receptors for three human proteins (fibrinogen, IgG, and beta 2-microglobulin (beta 2m)) was studied in group A streptococcal strains. M type 1, 12 and 14, and in M protein-negative variants of these strains. Fibrinogen binding was detected in all six strains. IgG did not bind to the two type-12 strains and uptake was low in both type-14 strains. The type-1, M protein-positive strain was negative in binding experiments with radiolabelled IgG, whereas the M protein-negative variant was strongly positive. Aggregated beta 2m showed a high degree of reactivity with the M protein-positive strains but not with the corresponding M protein-negative variants. The results indicate that the receptor for aggregated beta 2m is located on M protein in group A streptococci.
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D001609:Beta-Globulins / Q000378:metabolism*; D001665:Binding Sites; D005340:Fibrinogen / Q000378:metabolism; D006801:Humans; D007074:Immunoglobulin G / Q000378:metabolism; D011485:Protein Binding; D013297:Streptococcus pyogenes / Q000378:metabolism; D001613:beta 2-Microglobulin / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D001609:Beta-Globulins; D007074:Immunoglobulin G; D001613:beta 2-Microglobulin; D005340:Fibrinogen