title: IgA1 protease production by bacteria colonizing the upper respiratory tract.
abstract: Thirty-eight clinical isolates of Haemophilus influenzae and ten clinical isolates of Streptococcus pneumoniae were examined for IgA1 protease production. A suspension of surface material of each individual strain was incubated with human secretory IgA; IgA1 cleavage products were detected by SDS-PAGE and immunoblotting. The high incidence of IgA1 protease-positive strains (68.4% of the examined H. influenzae and 100% of the examined S. pneumoniae strains) confirms that IgA1 protease activity is a frequent characteristic of these two species. Yet the presence of this enzyme is, if at all, only a minor decisive factor for the induction of symptomatic infections of the upper respiratory tract by IgA1 protease-positive bacteria.
authors.affiliation: Universitätsklinik für Kinder und Jugendliche, Erlangen, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Zakrzewski
authors.forename: T
authors.initials: T
authors.lastname: Bechert
authors.forename: J P
authors.initials: JP
authors.lastname: Guggenbichler
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D006193:Haemophilus influenzae / Q000201:enzymology*; D006801:Humans; D015151:Immunoblotting; D007071:Immunoglobulin A, Secretory / Q000378:metabolism; D012141:Respiratory Tract Infections / Q000382:microbiology; D012697:Serine Endopeptidases / Q000378:metabolism*; D013296:Streptococcus pneumoniae / Q000201:enzymology*
chemical_list: D001426:Bacterial Proteins; D007071:Immunoglobulin A, Secretory; D012697:Serine Endopeptidases; C021433:IgA-specific serine endopeptidase