Institute of Food Research, Norwich Research Park, Norwich NR4 7UA, United Kingdom.
University of Cambridge, Department of Pathology, Cambridge CB2 1QP, United Kingdom; University of Cambridge, Department of Veterinary Medicine, Cambridge CB3 0ES, United Kingdom.
Curr Opin Immunol. 2017 Jun;46:23-29. doi: 10.1016/j.coi.2017.03.013. Epub 2017 Apr 21.
Almost all knowledge about the structure and function of MHC class II molecules outside of mammals comes from work with chickens. Most of the genes implicated in the class II system are present in chickens, so it is likely that the machinery of antigen processing and peptide-loading is similar to mammals. However, there is only one isotype (lineage) of classical class II genes, with one monomorphic DR-like BLA gene and two polymorphic BLB genes, located near one DMA and two DMB genes. The DMB2 and BLB2 genes are widely expressed at high levels, whereas the DMB1 and BLB1 genes are only expressed at highest levels in spleen and intestine, suggesting the possibility of two class II systems in chickens.
几乎所有关于 MHC Ⅱ类分子结构和功能的知识都来自于对禽类的研究。大多数与Ⅱ类系统相关的基因都存在于禽类中，因此抗原加工和肽加载的机制可能与哺乳动物相似。然而，只有一种经典的Ⅱ类基因同型（谱系），一个单态的 DR 样 BLA 基因和两个多态的 BLB 基因，位于一个 DMA 和两个 DMB 基因附近。DMB2 和 BLB2 基因广泛高水平表达，而 DMB1 和 BLB1 基因仅在脾和肠中最高水平表达，这表明禽类可能存在两种Ⅱ类系统。
