title: Genetic inactivation of the extracellular cysteine protease enhances in vitro internalization of group A streptococci by human epithelial and endothelial cells.
abstract: Group A Streptococcus (GAS) produces an extracellular cysteine protease (streptococcal pyrogenic exotoxin B) that participates in virulence. We examined two pairs of isogenic GAS strains (serotype M2 and M3) for ability to be internalized by human umbilical vein endothelial cells and A549 human lung fibroblasts. For both host cell types, the level of internalization by the cysteine protease-negative mutant strains was significantly greater than the wild type parent organisms. The data suggest that expression of the cysteine protease contributes to extracellular survival, an observation consistent with recent results from mouse infection studies (Lukomski et al., Infect immun 1998; 66: 771-6).
authors.affiliation: Institute for the Study of Human Bacterial Pathogenesis, Department of Pathology, Baylor College of Medicine, Houston, Texas, 77030, USA.
authors.forename: E H
authors.initials: EH
authors.lastname: Burns
authors.forename: S
authors.initials: S
authors.lastname: Lukomski
authors.forename: J
authors.initials: J
authors.lastname: Rurangirwa
authors.forename: A
authors.initials: A
authors.lastname: Podbielski
authors.forename: J M
authors.initials: JM
authors.lastname: Musser
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics*; D002460:Cell Line; D004730:Endothelium, Vascular / Q000166:cytology; D004847:Epithelial Cells / Q000502:physiology; D005098:Exotoxins / Q000235:genetics*; D005347:Fibroblasts / Q000382:microbiology / Q000502:physiology; D005798:Genes, Bacterial; D006801:Humans; D008168:Lung / Q000166:cytology; D008565:Membrane Proteins; D009154:Mutation; D010587:Phagocytosis; D013297:Streptococcus pyogenes / Q000201:enzymology* / Q000472:pathogenicity
chemical_list: D001426:Bacterial Proteins; D005098:Exotoxins; D008565:Membrane Proteins; C117980:SpeA protein, Streptococcus pyogenes; C027951:erythrogenic toxin