Different IgM+ B cell subpopulations residing within the peritoneal cavity of vaccinated rainbow trout are differently regulated by BAFF
Different IgM+ B cell subpopulations residing within the peritoneal cavity of vaccinated rainbow trout are differently regulated by BAFF
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DOI：
10.1016/j.fsi.2017.10.003
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发表时间：
2019-02-01
影响因子：
4.7
通讯作者：
Tafalla, Carolina
中科院分区：
文献类型：
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作者：
Granja, Aitor G.;Tafalla, Carolina
在硬骨鱼中，IgM（+）B细胞是腹膜腔中对抗炎性刺激的主要应答者之一，因为IgM（+）B细胞在腹膜内刺激后支配腹膜，也增加分泌的IgM的水平。BAFE是一种已知在B细胞生物学中起主要作用的细胞因子，已显示在抗原暴露后虹鳟鱼腹膜中其受体沿着上调，然而，这种反应背后的调节机制仍不清楚。在这项研究中，我们已经确定了两种不同的IgM（+）B细胞类型，存在于先前接种的虹鳟鱼（Oncorhynchus mykiss）IgD（+）IgM（hl）MHCIIhl细胞和IgD（-）IgM（lo）MHCIIlo细胞的腹腔中，前者类似于幼稚B细胞，后者类似于抗体分泌细胞。根据它们的膜IgM水平，这些细胞类型分别被命名为IgM（hl）和IgM（lo）B细胞。由于这些B细胞群体中的每一个对于不同的BAFF受体显示出不同的表达模式，我们研究了BAFF单独对每个细胞亚群的影响。重组BAFF在体外促进IgM（lo）而不是IgM（hl）B细胞的存活，导致IgM分泌细胞水平增加。相反，BAFF仅增加IgM（hl）B细胞上的膜MHC II水平，表明这些B细胞亚群具有不同的功能。此外，我们还发现腹膜IgM（hl）B细胞表达BAFF的水平与髓系细胞相当。这些结果表明BAFF是腹膜腔中B细胞稳态的主要调节剂，表明这种细胞因子可以以特定方式触发不同腹膜B细胞亚群上的不同信号。
In teleost fish, IgM(+) B cells are one of the main responders against inflammatory stimuli in the peritoneal cavity, as IgM(+) B cells dominate the peritoneum after intraperitoneal stimulation, also increasing the levels of secreted IgM. BAFE, a cytokine known to play a major role in B cell biology, has been shown to be up-regulated along with its receptors in the peritoneum of rainbow trout upon antigenic exposure, however, the regulatory mechanisms underneath this response remain unclear. In this study, we have identified two different IgM(+) B cell types residing in the peritoneal cavity of previously vaccinated rainbow trout (Oncorhynchus mykiss)IgD(+) IgM(hl) MHCIIhl cells, resembling naive B cells, and IgD(-) IgM(lo) MHCIIlo cells, resembling antibody-secreting cells. Based on their membrane IgM levels, these cell types were named IgM(hl) and IgM(lo) B cells, respectively. As each of these B cell populations showed a distinct expression pattern for the different BAFF receptors, we studied the effect of BAFF individually on each cell subset. Recombinant BAFF promoted the survival of IgM(lo) but not IgM (hl) B cells in vitro, resulting in increased levels of IgM-secreting cells. In contrast, BAFF increased the levels of membrane MHC II only on IgM(hl) B cells, suggesting different functions on these B cell subsets. Moreover, we also showed that peritoneal IgM(hl) B cells expressed BAFF at levels comparable to those seen on myeloid cells. These results point to BAFF as a main regulator of B cell homeostasis in the peritoneal cavity, suggesting that this cytokine can trigger different signals on different peritoneal B cell subsets in a specific manner.