title: Functional and serological analysis of type II immunoglobulin G-binding proteins expressed by pathogenic group A streptococci.
abstract: Bacterial immunoglobulin-binding proteins expressed on the surface of group A streptococci represent a heterogeneous family of functionally related proteins. In this report, we describe efficient methods for extracting immunoglobulin-binding proteins and classifying them functionally and antigenically. A common characteristic of immunoglobulin-binding proteins expressed by group A streptococci appears to be the absence of internal methionine residues in the binding protein. This has enabled development of a rapid, efficient, cyanogen bromide-based extraction procedure for solubilizing these molecules from intact bacteria. Studies carried out with a series of monospecific polyclonal antibodies prepared in chickens have identified two major antigenic classes of immunoglobulin-binding proteins. The methods described in this report facilitate a rapid functional and serological screening of immunoglobulin-binding proteins that should now enable detailed epidemiological studies of the importance of these molecules in group A streptococcal infections and their relationship to other surface proteins, in particular, the antiphagocytic M protein.
authors.affiliation: Department of Microbiology, Medical College of Ohio, Toledo 43699-0008.
authors.forename: R
authors.initials: R
authors.lastname: Raeder
authors.forename: R A
authors.initials: RA
authors.lastname: Otten
authors.forename: L
authors.initials: L
authors.lastname: Chamberlin
authors.forename: M D
authors.initials: MD
authors.lastname: Boyle
mesh_terms: D000942:Antigens, Bacterial / Q000145:classification / Q000302:isolation & purification; D001426:Bacterial Proteins / Q000302:isolation & purification / Q000378:metabolism*; D002352:Carrier Proteins / Q000145:classification / Q000302:isolation & purification / Q000378:metabolism*; D003488:Cyanogen Bromide; D006801:Humans; D007074:Immunoglobulin G / Q000302:isolation & purification / Q000378:metabolism*; D066298:In Vitro Techniques; D012995:Solubility; D013297:Streptococcus pyogenes / Q000276:immunology / Q000378:metabolism* / Q000472:pathogenicity; D014774:Virulence / Q000276:immunology
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D002352:Carrier Proteins; D007074:Immunoglobulin G; D003488:Cyanogen Bromide