2000 Fiscal Year Final Research Report Summary
Secretory IgA-mediated basophil activation. Its mechanisms and implication in allergy.
| Project/Area Number |
11670440
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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 |
内科学一般
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| Research Institution | University of Tokyo |
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Principal Investigator |
YAMAGUCHI Masao University of Tokyo Hospital Assistant professor, 医学部・附属病院, 助手 (10302704)
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| Co-Investigator(Kenkyū-buntansha) |
HIRAI Koichi University of Tokyo, Graduate School of Medicine, Associate professor, 大学院・医学系研究科, 客員助教授 (10156630)
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| Project Period (FY) |
1999 – 2000
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| Keywords | secretory IgA / basophils / allergy |
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| Research Abstract |
Secretory IgA (sIgA) is the most abundant Ig isotype in mucous secretions in the upper and lower airways, where basophils exert effector functions during allergic inflammation. We recently demonstrated that immobilized sIgA on Sepharose beads is capable of inducing basophil degranulation (〜15% of total histamine). To investigate the detailed mechanisms of this degranulation, we established in this study a new assay system for sIgA-mediated basophil activation. Immobilized sIgA on a plastic surface induced strong histamine release (〜50% of total histamine) comparable to anti-IgE, and we analyzed the nature of basophil signal transduction by sIgA using various inhibitors. sIgA-induced basophil histamine release was inhibited completely by pertussis toxin, but anti-IgE-induced release was not affected. sIgA-mediated release was also inhibited by phosphatidylinositol 3-kinase (PI 3-kinase) inhibitor, wortmannin. These results strongly suggest that sIgA activates basophils via an IgE-independent novel mechanism involving both Gi protein and PI 3-kinase.
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