1996 Fiscal Year Final Research Report Summary
Sialidase on T cells and B cell activation
| Project/Area Number |
07808069
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Functional biochemistry
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
OCHIAI Shigeko Hokkaido Univ., Inst.of Immunol.Science, Associate Prof., 免疫科学研究所, 助教授 (20001878)
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| Project Period (FY) |
1995 – 1996
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| Keywords | Thymus-sialidase / age-depend-sialidase / neutral-sialdase / membrane bound-sialidase / mouse |
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| Research Abstract |
We have shown that IgE low affinity receptor, CD23, has a lectin activity as galactose-binding (1) and that sialidase-treatment causes large aggregations of EBV-transformed B cells which have CD23 on the cell surface (2). The removal of sialic acid from B cells seems to be important for B-B or T-B cell interactions.Thus we studied on sialidase which acts at nutral pH in immunological tissues.
Membrane-bound sialidase activity acting at neutral pH was found to be high in the thymus as well as being age-dependent ; It was not found in mature and immature T cells, but was detected in a NP-40 solubilized fraction from cells other than T cells. This enzyme activity showed optimum pH at 6.5 and was inhibited completely by 1mM Cu++. Histochemical staining of the cell which showed sialidase activity revealed that the cells were located sparsely in the area of the medullar of the thymus. They were not epithelial cells, but shown to possess immunoglobulin and Mac-1 antigen on the cell surface. This is the first report of this type of cells containing sialidase.
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