Glycosylation-dependent interaction of Jacalin with CD45 induces T lymphocyte activation and Th1/Th2 cytokine secretion
Glycosylation-dependent interaction of Jacalin with CD45 induces T lymphocyte activation and Th1/Th2 cytokine secretion
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DOI：
10.1189/jlb.1106660
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发表时间：
2007-04-01
影响因子：
5.5
通讯作者：
Kawasaki, Toshisuke
中科院分区：
文献类型：
--
作者：
Baba, Makoto;Ma, Bruce Yong;Kawasaki, Toshisuke
Jacalin, an (alpha-O-glycoside of the disaccharide Thomsen-Friedenreich antigen (galactose (beta 1-3 N-acetylgalactosamine, T-antigen)-specific lectin from jackfruit seeds, has been shown to induce mitogenic responses and to block infection by HIV-1 in CD4(+) T lymphocytes. The molecular mechanism underlying Jacalin-induced T cell activation has not been elucidated completely yet. In the present study, protein tyrosine phosphatase (PTPase) CD45 was isolated from a Jurkat T cell membrane fraction as a major receptor for Jacalin through affinity chromatography and mass spectrometry. CD45, which is highly glycosylated and expressed exclusively on the surface of lymphocytes, is a key regulator of lymphocyte signaling, playing a pivotal role in activation and development. We found that the lectin induced significant IL-2 production by a CD45-positive Jurkat T cell line (JE6.1) and primary T cells. However, this effect did not occur in a CD45-negative Jurkat T cell line (J45.01) and was blocked completely by a specific CD45 PTPase inhibitor in Jurkat T (JE6.1) and primary T cells. Furthermore, we also observed that Jacalin caused a marked increase in IL-2 secretion in response to TCR ligation and CD28 costimulation and contributed to Th1/Th2 cytokine production by activating CD45. Jacalin increased CD45 tyrosine phosphatase activity, which resulted in activation of the ERK1/2 and p38 MAPK cascades. Based on these findings, we propose a new, immunoregulatory model for Jacalin, wherein glycosylation-dependent interactions of Jacalin with CD45 on T cells elevate TCR-mediated signaling, which thereby up-regulate T cell activation thresholds and Th1/Th2 cytokine secretion.
