Binding of aggregated human serum albumin to M12 and some other types of group A streptococci.
In radiobinding tests many group A, C and G streptococci react with IgG and IgA, irrespective of the antigen-combining sites, as well as with various other serum proteins, e.g. human serum albumin (HSA). The present study demonstrated that glutaraldehyde-aggregated, radiolabelled HSA (a*HSA), in comparison to monomeric HSA, binds more avidly to streptococci. Of group A streptococci, strains representing types M6, M12, M18, M46, M55 and M57 displayed pronounced binding of a*HSA whereas a number of other serotypes were non-reactive. The streptococcal sites involved proved to be relatively heat-resistant and highly sensitive to trypsin treatment. Human fibrinogen counteracted the binding of a*HSA. The uptake by M12 was inhibited strongly by rabbit antiserum raised against M12, whereas other antisera were less active. The results suggest that the bacterial structure binding a*HSA is a protein and that, in at least one serotype, M12, the binding occurs to the M-protein.
D000268:Adhesiveness; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins / Q000378:metabolism*; D002352:Carrier Proteins; D005340:Fibrinogen / Q000494:pharmacology; D005976:Glutaral / Q000494:pharmacology; D006358:Hot Temperature; D006801:Humans; D006863:Hydrogen-Ion Concentration; D011485:Protein Binding; D012703:Serotyping; D012709:Serum Albumin / Q000378:metabolism*; D013045:Species Specificity; D013297:Streptococcus pyogenes / Q000145:classification / Q000378:metabolism* / Q000502:physiology; D014357:Trypsin / Q000494:pharmacology
D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D002352:Carrier Proteins; D012709:Serum Albumin; C014689:streptococcal M protein; D005340:Fibrinogen; D014357:Trypsin; D005976:Glutaral