| 研究実績の概要 |
It has been largely unknown how IgE production is regulated and how IgE B-cell memory is generated in allergic patients. However, there are technical limitations in identifying rare IgE+ B cells, especially in humans. Adopting the Fas-mediated Ag-specific iGB cell selection (FAIS) system, I have developed a system to selectively expand IgE+ B cells by a four-step B cell culture procedure. 1) Culture with IL-21 on feeder cells expressing exogenous CD40L and BAFF (40LB). 2) Stimulation culture on 40LB cells expressing FcεR1 to stimulate IgE+ iGB cells. 3) Selection culture on 40LB cells expressing the Fas ligand: all but IgE+ iGB cells undergo apoptosis. 4) Recovery culture on 40LB cells. Starting with blood B cells of hay fever allergic donors, I successfully obtained an almost pure population of IgE+ B cells with this procedure in combination with cell sorting. I found 30 mutations in genomic genes of mIgE+ Bm cells by comparing with non-B leukocytes from the same patients of various allergic diseases, using whole-exome sequencing. The mutant genes mainly express on the membrane and the endoplasmic reticulum. Their functions are cell-cell interaction, ER stress, apoptosis, cell proliferation, endocytosis, and ubiquitination. Especially, I found that allergic IgE+ B cells have IgE-endocytosis defects. Altogether, the mutations in endocytosis-related genes (LRP6, MICALL1, EPS15, and ACK1) may lead to the survival of allergic IgE+ B cells then the allergic disease.
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