| Co-Investigator(Kenkyū-buntansha) |
NAKAGAWA Ichiro Graduate School of Dentistry, Osaka University, Assistant Professor, 大学院・歯学研究科, 講師 (70294113)
KAWABATA Shigetaka Graduate School of Dentistry, Osaka University, Associate Professor, 大学院・歯学研究科, 助教授 (50273694)
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| Research Abstract |
The results obtained by this study suggest that
1. Streptococcus pyogenes can be internalized into human pharyngeal epithelial cells with considerably high frequencies. Furthermore, the presence of hyaluronic acid of S. pyogenes decreases the invasion efficiency.
2. All the S. pyogenes strains possess the fbp54 gene encoding fibronectin-binding protein FBP54, which is a promising vaccine for the prevention of S. pyogenes infections.
3. The internalization of S. pyogenes in epithelial cells is necessary and sufficient for the induction of apoptosis, which is initiated by mitochondrial dysfunction, and the mechanism of S. pyogenes-induced apoptosis is clearly different from that induced by other intracellular invasive bacteria, e.g. Shigella and Salmonella species.
4. Protein Fba promotes S. pyogenes entry into human epithelial cells. This protein possesses three or four proline-rich repeat domains and exhibits a high homology to FnBPA, the fibronectin-binding protein of Staphylocaccus aureus. The fba gene is found in M types 1, 2, 4, 22, 28, and 49 of S. pyogenes, and is transcribed under the control of the Mga regulator.
5. Administration of superantigens protect mice from infection with intracellular bacteria such as Listeria, which is dependent on the enhanced Listeria-specific CTL activity in the presence of CD4^+ T cells, and superantigens exhibit adjuvant activity in the immunization against intracellular pathogens.
6. Protein Lbp possesses laminin-binding activity and is involved in adhesion to pharyngeal epithelial cell.
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