| Project/Area Number |
10470068
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Bacteriology (including Mycology)
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| Research Institution | Gifu University |
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Principal Investigator |
EZAKI Takayuki Gifu University School of Medicine, Professor, 医学部, 教授 (90151977)
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| Co-Investigator(Kenkyū-buntansha) |
KAWAMURA Yoshiaki Gifu University School of Medicine, Assistant, 医学部, 助手 (80262757)
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| Project Period (FY) |
1998 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥4,400,000 (Direct Cost: ¥4,400,000)
Fiscal Year 1999: ¥4,400,000 (Direct Cost: ¥4,400,000)
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| Keywords | Pathogenicity / Sugar protein / Surface antigen / Intracellular growth / Salmonella typhi / Macrophage / 食細胞内寄生 / 侵入 / 病原因子 / サルモネラ |
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| Research Abstract |
Salmonella typhi is known as an intracellular pathogen because the organism survives inside macrophages. The surface of the bacteria is covered with Vi polysaccharide, N-acetyl galactosamine-uronic acid homopolymer. The expression of the antigen is controlled by osmolarity and other environmental factors. When the organism invades from intestinal epithelium. The s. typhi suppresses surface Vi antigen and produces flagellin and secreted proteins, these factors promote the bacterial invasion from the surface of M cells of Peyer's patches. The Vi suppressed S. typhi agglutinate with human blood type antigen. The surface omp C protein of S. typhi was responsible for this agglutination, This agglutination maybe promote bacterial entry into epithelial cells.
Vi expression is promoted in blood and inside macrophages, Vi deleted mutants cannot survive in serum and quickly killed by complement. Vi was maximally expressed inside macrophages, Vi deleted mutants stimulated macrophages during the entry into macrophages and quickly processed by macrophages, This means that S. typhi needs to mask surface antigen to enter macrophage because Vi deleted S, typhi quickly stimulated macrophages. LPS nonresponsive macrophages cell line could not activated during the entry of Vi deleted macrophages. This suggests that recognition of LPS receptor play a major role to recognize bacterial entry and processing of ingested bacteria.
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