Background: Complement activation has been implicated in the development of the instant blood-mediated inflammatory reaction (IBMIR). In particular, anaphylatoxins C3a and C5a elicit a broad range of proinflammatory effects, including chemotaxis of inflammatory cells and cytokine release. We have previously shown that 2 types of receptors for C5a are expressed on isolated islets. In the present study, we investigated this component in detail. Methods: C3aR, C5aR, and C5L2, together with CD11b and CD31, on freshly isolated islets (fresh group) and islets cultured with (cytokine group) or without (culture group) TNF-α, IL-1β, and IFN-γ for ∼12 hours were analyzed by flow cytometry. In addition, these 3 kinds of receptors were analyzed on nonendocrine cells. Results: C5aR and C5L2 were expressed on the isolated islets (C5aR: 7.91 ± 2.83%; C5L2: 2.45 ± 1.34%) and the expression of both C5a receptors was markedly attenuated by culture for 12 hours (C5aR: P <.005; C5L2: P <.05). Compared with the culture group, the expression was significantly up-regulated in the cytokine group (C5aR: P <.05; C5L2: P =.05). C5aR-positive cells expressed CD11b but not CD31. In contrast to islets, nonendocrine cells expressed C5L2 predominantly. C3aR was scarcely expressed on isolated islets or nonendocrine cells. Conclusions: These data suggest that C5aR and C5L2 are expressed on CD11b-positive leukocytes in islet preparations. Depletion of C5a receptors by culturing appropriately could be an attractive therapeutic strategy in clinical islet transplantation.
|Number of pages||2|
|Publication status||Published - 2011 Nov|
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