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IgA1 protease production by bacteria colonizing the upper respiratory tract
J Zakrzewski1, T Bechert, J P Guggenbichler
1Universitätsklinik für Kinder und Jugendliche, Erlangen, Germany.
Infection
|April 30, 1998
Summary
Most Haemophilus influenzae and Streptococcus pneumoniae strains produce IgA1 protease, an enzyme that cleaves immunoglobulin A1. However, this enzyme
Area of Science:
- Microbiology
- Immunology
- Bacterial Pathogenesis
Background:
- IgA1 protease is an enzyme produced by certain bacteria.
- Secretory IgA (sIgA) is a key component of mucosal immunity.
- Haemophilus influenzae and Streptococcus pneumoniae are common causes of upper respiratory tract infections.
Purpose of the Study:
- To determine the prevalence of IgA1 protease production in clinical isolates of H. influenzae and S. pneumoniae.
- To assess the role of IgA1 protease in the development of symptomatic upper respiratory tract infections.
Main Methods:
- Clinical isolates of H. influenzae and S. pneumoniae were cultured.
- Bacterial surface material was incubated with human secretory IgA.
- IgA1 cleavage products were analyzed using SDS-PAGE and immunoblotting.
Main Results:
- A high incidence of IgA1 protease-positive strains was observed: 68.4% for H. influenzae and 100% for S. pneumoniae.
- The presence of IgA1 protease was confirmed as a frequent characteristic of these bacterial species.
Conclusions:
- IgA1 protease production is common in H. influenzae and S. pneumoniae.
- While prevalent, IgA1 protease activity appears to be a minor factor in causing symptomatic upper respiratory tract infections by these bacteria.