Centro de Investigación en Sanidad Animal (CISA-INIA), Valdeolmos, Madrid, Spain.
PLoS One. 2013 Dec 6;8(12):e82737. doi: 10.1371/journal.pone.0082737. eCollection 2013.
TWO major classes of b lymphocytes have been described to date in rainbow trout: IgM(+) and IgT(+) cells. IgM(+) cells are mainly localized in the spleen, peripheral blood and kidney but are also found in other tissues. However, differences among IgM(+) cell populations attending to its location are poorly defined in fish. Thus, the aim of this work was to characterize the expression of different immune molecules such as chemokine receptors, Toll-like receptors (TLRs) and transcription factors on sorted IgM(+) lymphocytes from different rainbow trout tissues. IgM(+) populations from blood, spleen, kidney, gills, intestine and liver were isolated by cell sorting and the constitutive levels of transcription of these genes evaluated by real-time PCR. To further characterize B cells, we identified an MS4A sequence. In humans, the MS4A family includes several genes with immune functions, such as the B cell marker CD20 or FcRβ. Subsequently, we have also evaluated the mRNA levels of this MS4A gene in the different IgM(+) populations. The relevant differences in transcriptional patterns observed for each of these IgM(+) populations analyzed, point to the presence of functionally different tissue-specific B cell populations in rainbow trout. The data shown provides a pattern of genes transcribed in IgM(+) B cells not previously revealed in teleost fish. Furthermore, the constitutive expression of all the TLR genes analyzed in IgM(+) cells suggests an important role for these cells in innate immunity.
迄今为止，已在虹鳟鱼中描述了两种主要的 B 淋巴细胞类群：IgM(+)和 IgT(+)细胞。IgM(+)细胞主要定位于脾脏、外周血和肾脏，但也存在于其他组织中。然而，鱼类中 IgM(+)细胞群体因其位置而异的差异尚未得到明确界定。因此，本研究的目的是表征不同免疫分子（如趋化因子受体、Toll 样受体 (TLR) 和转录因子）在不同虹鳟鱼组织中分离的分选 IgM(+)淋巴细胞上的表达。通过细胞分选从血液、脾脏、肾脏、鳃、肠和肝脏中分离出 IgM(+)群体，并通过实时 PCR 评估这些基因的转录水平。为了进一步表征 B 细胞，我们鉴定了一个 MS4A 序列。在人类中，MS4A 家族包括几个具有免疫功能的基因，如 B 细胞标记物 CD20 或 FcRβ。随后，我们还评估了不同 IgM(+)群体中该 MS4A 基因的 mRNA 水平。对每种分析的 IgM(+)群体观察到的转录模式的相关差异表明，虹鳟鱼中存在功能不同的组织特异性 B 细胞群体。所显示的数据提供了在之前的硬骨鱼类中未揭示的 IgM(+)B 细胞转录的基因模式。此外，所有 TLR 基因在 IgM(+)细胞中的组成型表达表明这些细胞在先天免疫中具有重要作用。
