CCR7 Is Mainly Expressed in Teleost Gills, Where It Defines an IgD+IgM- B Lymphocyte Subset
CCR7 Is Mainly Expressed in Teleost Gills, Where It Defines an IgD+IgM- B Lymphocyte Subset
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DOI：
10.4049/jimmunol.1302471
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发表时间：
2014-02-01
影响因子：
4.4
通讯作者：
Tafalla, Carolina
中科院分区：
文献类型：
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作者：
Castro, Rosario;Bromage, Erin;Tafalla, Carolina
趋化因子受体CCR 7是CCL 19和CCL 21趋化因子的受体，调节循环白细胞向次级淋巴组织（如淋巴结和派尔集合淋巴结）的募集和聚集。尽管硬骨鱼没有这些二级淋巴结构，我们最近报道了一个同源的CCR 7虹鳟鱼（虹鳟鱼mykiss）。在目前的工作中，我们已经通过流式细胞术研究了携带细胞外CCR 7的白细胞在幼稚成体组织中的分布，观察到在不同的白细胞群体中，具有膜（CR 7）CCR 7的细胞的最高数量记录在鳃中（7.5 +/-2%CCR7（+）细胞）。相比之下，头肾、脾脏、胸腺、肠和外周血中CCR 7（+）细胞的比例< 5%。当在早期发育阶段研究CCR 7时，我们检测到在整个发育过程中鳃中的基因表达和蛋白质CCR 7水平逐渐增加。令人惊讶的是，鳃中的大多数CCR 7（+）细胞不是髓样细胞，不表达膜CD 8、IgM和IgT，但在细胞表面表达IgD。事实上，鳃中的大多数IgD（+）细胞表达CCR 7。有趣的是，IgD（+）CCR 7（+）群体并不共表达IgM。最后，当鳟鱼浴攻击病毒性出血性败血症病毒，CCR 7+细胞的数量显着减少，而在头肾显着增加鳃。这些结果提供了证据表明，鳟鱼中存在一种新的IgD（+）IgM（-）B淋巴细胞亚群，该亚群表达（+）CCR 7并对病毒感染有反应。与IgD（+）IgM（-）亚型在哺乳动物中的相似性进行了讨论。
Chemokine receptor CCR7, the receptor for both CCL19 and CCL21 chemokines, regulates the recruitment and clustering of circulating leukocytes to secondary lymphoid tissues, such as lymph nodes and Peyer's patches. Even though teleost fish do not have either of these secondary lymphoid structures, we have recently reported a homolog to CCR7 in rainbow trout (Oncorhynchus mykiss). In the present work, we have studied the distribution of leukocytes bearing extracellular CCR7 in naive adult tissues by flow cytometry, observing that among the different leukocyte populations, the highest numbers of cells with membrane (mem) CCR7 were recorded in the gill (7.5 +/- 2% CCR7(+) cells). In comparison, head kidney, spleen, thymus, intestine, and peripheral blood possessed < 5% CCR7(+) cells. When CCR7 was studied at early developmental stages, we detected a progressive increase in gene expression and protein CCR7 levels in the gills throughout development. Surprisingly, the majority of the CCR7(+) cells in the gills were not myeloid cells and did not express membrane CD8, IgM, nor IgT, but expressed IgD on the cell surface. In fact, most IgD(+) cells in the gills expressed CCR7. Intriguingly, the IgD(+)CCR7(+) population did not coexpress (mem)IgM. Finally, when trout were bath challenged with viral hemorrhagic septicemia virus, the number of CCR7 + cells significantly decreased in the gills while significantly increased in head kidney. These results provide evidence of the presence of a novel(mem)IgD(mem)(+)IgM(-) B lymphocyte subset in trout that expresses (mem)CCR7 and responds to viral infections. Similarities with IgD(+) IgM(-) subsets in mammals are discussed.