The major histocompatibility complex (MHC) class I genes play a critical role within the immune system, both by the presentation of antigens from intracellular pathogens to immunocompetent cells and by the interaction with killer cell immunoglobulin-like receptors (KIR) on natural killer cells (NK cells). Genes of the MHC are highly diverse, and MHC variation can have effects on the immune functionality of individuals; hence, comparisons of MHC diversity among closely related phylogenetic taxa may give insight into the factors responsible for the shaping of its diversity. The four geographically separated chimpanzee subspecies differ in their overall genetic diversity, have different population histories, and are confronted with different pathogens in their natural habitat, all of which may affect MHC class I DNA sequence diversity. Here, we compare the MHC-B exon two DNA sequence diversity from 24 wild western and 46 wild eastern chimpanzees using necropsy and noninvasively collected fecal samples, respectively. We found a higher MHC-B exon two nucleotide diversity, in our western than eastern chimpanzees. The inclusion of previously published MHC-B exon two data from other western and eastern chimpanzees supported this finding. In addition, our results confirm and extend the finding of a very low C1 epitope frequency at eastern chimpanzee MHC-B molecules, which likely affects the ability of these molecules to interact with NK cells. While the understanding of the differing pathogen environments encountered by disparate populations of a species is a challenging endeavor, these findings highlight the potential for these pathogens to selectively shape immune system variation.

中文翻译：

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在不同 MHC-B 多样性和KIR表位在野生黑猩猩的两个群体

主要的组织相容性复合体（MHC）I类基因在免疫系统中起着至关重要的作用，既可以将抗原从胞内病原体呈递给免疫活性细胞，又可以与自然杀伤细胞上的杀伤细胞免疫球蛋白样受体（KIR）相互作用（ NK细胞）。MHC的基因高度多样化，MHC的变异可能会影响个体的免疫功能。因此，比较密切相关的系统发生类群中的MHC多样性可以深入了解造成其多样性形成的因素。四个地理上分离的黑猩猩亚种的整体遗传多样性不同，具有不同的种群历史，并且在其自然栖息地中面临着不同的病原体，所有这些都可能影响MHC I类DNA序列的多样性。这里， MHC-B 外显子分别使用尸检和非侵入性收集的粪便样本从24个野生西部黑猩猩和46个野生东部黑猩猩中获得两个DNA序列多样性。我们在西部黑猩猩中发现了比东部黑猩猩更高的 MHC-B 外显子两个核苷酸多样性。包含以前发布的 MHC-B 外显子来自其他西部和东部黑猩猩的两个数据支持了这一发现。此外，我们的结果证实并扩展了在东部黑猩猩MHC-B分子中发现极低的C1表位频率的发现，这很可能会影响这些分子与NK细胞相互作用的能力。尽管了解物种的不同种群所遇到的不同病原体环境是一项艰巨的任务，但这些发现凸显了这些病原体选择性影响免疫系统变异的潜力。