Immunology Unit, University of Veterinary Medicine, Hannover, Germany.
PLoS One. 2013 Aug 14;8(8):e71502. doi: 10.1371/journal.pone.0071502. eCollection 2013.
Murine and human peripheral blood monocytes are heterogeneous in size, granularity, nuclear morphology, phenotype and function. Whether and how bovine blood monocytes follow this pattern was analyzed in this study. Flow cytometrically, classical monocytes (cM) CD14⁺CD16⁻, intermediate monocytes (intM) CD14⁺ CD16⁺ and nonclassical monocytes (ncM) CD14⁺ CD16⁺ were identified, with cM being the predominant subset (89%). cM showed a significant lower expression of CD172a, intM expressed the highest level of MHC class II molecules, and ncM were low positive for CD163. Compared to cM and intM, ncM showed a significantly reduced phagocytosis capacity, a significantly reduced generation of reactive oxygen species, and reduced mRNA expression of CXCL8, CXCL1 and IL-1β after LPS stimulation. Based on IL-1β secretion after LPS/ATP stimulation, the inflammasome could be activated in cM and intM, but not in ncM. IFNγ increased the expression of CD16 selectively on cM and induced a shift from cM into intM in vitro. In summary, bovine CD172a-positive mononuclear cells define three monocyte subsets with distinct phenotypic and functional differences. Bovine cM and intM share homologies with their human counterparts, whereas bovine ncM are not inflammatory monocytes.
鼠类和人类外周血单核细胞在大小、颗粒度、核形态、表型和功能上存在异质性。本研究分析了牛血液单核细胞是否遵循这一模式以及如何遵循这一模式。通过流式细胞术，鉴定出经典单核细胞（cM）CD14 ⁺ CD16 ⁻ 、中间单核细胞（intM）CD14 ⁺ CD16 ⁺ 和非经典单核细胞（ncM）CD14 ⁺ CD16 ⁺ ，其中 cM 是主要亚群（89%）。cM 表现出 CD172a 的显著低表达，intM 表达最高水平的 MHC Ⅱ类分子，而 ncM 对 CD163 呈低度阳性。与 cM 和 intM 相比，ncM 的吞噬能力显著降低，产生的活性氧显著减少，LPS 刺激后 CXCL8、CXCL1 和 IL-1β 的 mRNA 表达减少。基于 LPS/ATP 刺激后 IL-1β 的分泌，cM 和 intM 中的炎症小体可以被激活，但 ncM 中不能。IFNγ 选择性地上调 cM 中 CD16 的表达，并在体外诱导 cM 向 intM 转化。总之，牛 CD172a 阳性单核细胞定义了具有明显表型和功能差异的三个单核细胞亚群。牛 cM 和 intM 与人对应的细胞具有同源性，而牛 ncM 不是炎症性单核细胞。
