Li Yi-Qun, Sun Li, Li Jun
Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, China; University of Chinese Academy of Sciences, Beijing, 100039, China.
Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, China.
Dev Comp Immunol. 2018 May;82:31-38. doi: 10.1016/j.dci.2017.12.028. Epub 2018 Jan 2.
Increasing evidence has demonstrated support for the endocytic capacities of teleost B cells. In the present study, the ability of turbot IgM B cells to ingest microspheres of different sizes and the corresponding internalization pathways were investigated. The results showed that IgM B cells exhibited relatively high endocytic capacities for 0.5 μm and 1 μm latex beads, and that different mechanisms were employed for IgM and IgM cells to uptake 0.5 μm and 1 μm beads. For 0.5 μm beads, IgM B cells apparently employed macropinocytosis-dependent endocytic pathway, whereas IgM cells utilized a different process involving both clathrin- and caveolae-mediated pathways. For the uptake of 1 μm beads, IgM cells relied mainly on macropinocytosis and partially on caveolae-mediated pathway, while IgM cells utilized the routes similar to that of internalizing 0.5 μm beads. Consistently, the internalized microspheres were co-localized with high-molecular-mass dextran in IgM phagocytic cells. In addition to latex beads, IgM B cells could also ingest inactivated bacteria predominately through macropinocytosis and caveolae-mediated endocytosis. These results collectively indicated that macropinocytosis is principally responsible for particle uptake by turbot IgM B cells.
越来越多的证据表明硬骨鱼B细胞具有内吞能力。在本研究中，研究了大菱鲆IgM B细胞摄取不同大小微球的能力及其相应的内化途径。结果表明，IgM B细胞对0.5μm和1μm的乳胶珠表现出较高的内吞能力，并且IgM和IgM细胞摄取0.5μm和1μm珠子采用了不同的机制。对于0.5μm的珠子，IgM B细胞显然采用了依赖巨胞饮作用的内吞途径，而IgM细胞则利用了一种涉及网格蛋白介导和小窝介导途径的不同过程。对于1μm珠子的摄取，IgM细胞主要依赖巨胞饮作用，部分依赖小窝介导途径，而IgM细胞利用的途径与内化0.5μm珠子的途径相似。同样，内化的微球在IgM吞噬细胞中与高分子量葡聚糖共定位。除乳胶珠外，IgM B细胞还可以主要通过巨胞饮作用和小窝介导的内吞作用摄取灭活细菌。这些结果共同表明，巨胞饮作用是大菱鲆IgM B细胞摄取颗粒的主要原因。
