| Budget Amount *help |
¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2009: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2008: ¥3,120,000 (Direct Cost: ¥2,400,000、Indirect Cost: ¥720,000)
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| Research Abstract |
CD8 is mainly expressed on cytotoxic T lymphocytes. In this study, CD8+ monocytes in human peripheral blood were identified by whole blood erythrocyte lysis method in flow cytometry. CD8 molecules on monocytes were constituted by CD8α and CD8 β subunits; however, the mRNA expression of neither CD8α nor CD8β was detected in CD8+ monocytes. We therefore hypothesized that CD8 molecules were transferred to monocytes from cells other than monocytes. Initially, it was shown that serum was essential for the detection of CD8+ monocytes. Next, we revealed that CD8 molecules were derived from T cells, and that cell-to-cell contact between the monocytes and T cells was required for the transfer of CD8 molecules to monocytes. Furthermore, Fcγ receptor II (CD32) on monocytes and dynamism of cell membrane and cytoskeleton were involved in the mechanism of the CD8 translocation. Interestingly, CD3 and αβT cell receptor (TCR) were also transferred from T cells to monocytes accompanied by CD8. Collective evidences indicated that cell surface CD8, and also CD3 and αβTCR molecules on T cells, were transferred to monocytes via an intercellular exchange of plasma membrane, which is recently termed trogocytosis, under the presence of serum and the anti-CD8 monoclonal antibody.
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