Data from: Major Histocompatibility Complex class IIb polymorphism influences gut microbiota composition and diversity

Individuals harbor diverse communities of symbiotic bacteria, which differ dramatically among host individuals. This heterogeneity poses an immunological challenge of distinguishing between mutualistic and pathogenic members of diverse and host-specific microbial communities. We propose that Major Histocompatibility class II (MHC) genotypes contribute to recognition and regulation of gut microbes, and thus MHC polymorphism contributes to microbial variation among hosts. Here, we confirm that, within a single wild vertebrate population of threespine stickleback, different MHC II amino acid sequence motifs are associated with among-individual variation in gut microbiota. The presence of certain MHC motifs is associated with altered relative abundance (increase or decrease) of some microbial Families. Furthermore, hosts with more diverse MHC motifs had less diverse gut microbiota. Our results show that MHC affects host regulation of gut microbiota in natural populations, consistent with limited experimental evidence that MHC controls gut microbes in laboratory mice. One implication is that MHC might influence the efficacy of therapeutic strategies to treat dysbiosis-associated disease. For example, we hypothesize that microbial transplants to treat dysbiosis might be constrained by MHC match between donor and recipient. Another implication is that macroparasite-driven selection on MHC has the potential to indirectly alter the host gut microbiota, and vice versa. Our findings therefore open up a variety of avenues for further investigation into MHC-microbiota interactions.宿主个体携带着多样的共生细菌群落，且不同宿主个体间的群落组成存在显著差异。这种群落异质性构成了免疫学层面的一项挑战：即如何在多样且具有宿主特异性的微生物群落中，区分互利共生与致病的微生物类群。我们提出，主要组织相容性复合体II类（Major Histocompatibility class II）基因型参与肠道微生物的识别与调控，因此MHC的多态性是导致宿主间微生物群落差异的重要因素之一。本研究证实，在一个野生三棘刺鱼（threespine stickleback）脊椎动物种群中，不同的MHC II类氨基酸序列基序与个体间肠道微生物群落的差异存在显著关联。特定MHC基序的存在，与部分微生物科的相对丰度改变（升高或降低）密切相关。此外，拥有更多样化MHC基序的宿主，其肠道微生物群落的多样性反而更低。我们的研究结果表明，在自然种群中，MHC会调控宿主的肠道微生物群落，这与实验室小鼠中MHC调控肠道微生物的有限实验证据相一致。该研究的一项启示是，MHC可能会影响菌群失调相关疾病治疗策略的有效性。例如，我们提出假说：用于治疗菌群失调的微生物移植疗法，可能会受到供体与受体间MHC匹配度的限制。另一项启示是，大型寄生虫对MHC的选择压力，有可能间接改变宿主的肠道微生物群落，反之亦然。因此，我们的研究发现为MHC与肠道微生物群落的互作研究开辟了诸多全新的探索方向。