LACK OF INTERFERENCE BETWEEN IGA-BINDING PROTEINS AND IGA PROTEASES OF HUMAN PATHOGENIC BACTERIA

Some human bacterial pathogens produce specific immunoglobulin A1 (IgA 1) proteases that cleave the heavy chain of human IgA1, generating int act Fab and Fc fragments, Other pathogenic bacterial species express s urface proteins which bind to the Fc part of human IgA in a non-immune manner, To analyse whether IgA-binding proteins affect the activity o f IgA1 proteases, the ability of seven different IgA1 proteases to hyd rolyse IgA1 in the presence of either of two different bacterial IgA-b inding proteins was tested, Data obtained in two different types of ex periment suggest that IgA1 bound to IgA-binding proteins still functio ns as a substrate for IgA1 proteases, As Fc fragments produced by clea ving IgA1 with IgA1 proteases still bind to IgA-binding proteins, we c onclude that these two types of bacterial protein act independently of each other.