动物实验,适应性免疫,肠道菌群 z-bo 2020-09-29 1179

　　Adaptive immunity is a fascinating biological phenomenon that only exists in jawbone vertebrates. It changes the receptor lineage and "remembers" previous contact with pathogens in the life of an individual. It is easier to prevent or treat subsequent infections of the same pathogen, and is characterized by manufacturing capabilities. Although the role of adaptive immunity in disease resistance has been well documented, its role in symbiotic microbial communities is still unclear, leading to a new conceptual model "ecological filter". There is increasing evidence that the immune system can act as an ecological filter for microbial communities in human and animal models. Related research on the entire genome and quantitative trait locus mapping studies have found that there is a significant correlation between immune genes and the composition of human and mouse microflora. In addition, studies have shown that the physical interaction between immune receptors and gut microbial populations will affect their composition and diversity, which in turn affects the health of the host. Direct manipulation of the host's adaptive immune system also showed significant changes in the intestinal flora. However, in these studies, especially in mouse studies, there are usually small samples or their design cannot distinguish different phenotype mice and genotype specificity in different cages, and can be clearly identified. hardly. Ecological filtration is carried out in various cages.

　　Zebrafish is an excellent model for testing the effect of adaptive immune filtering. Zebrafish can make up for many of the shortcomings of mouse and human research. 1. The adaptive immune system of zebrafish is very similar to that of mammals. 2. Many breeding pairs can be used in a single experiment from a single source. 3. You can easily control the breeding conditions and sample the shared environment perfectly. four. Innate immunity is feasible during incubation, but adaptive immunity in zebrafish is feasible. It can run perfectly between the 21st and the 28th, making it easier for experimenters to resolve differences in immunization methods. By recording the changes in the composition of the gut microbial community during the development of zebrafish, it can be seen that since 21dpf, although the breeding conditions and diet levels have not changed, the microbial composition has changed significantly. As an ecological filter of gut microbes, adaptive immunity is a variable for community development by adjusting data to an ecological model with only a neutral community construction process (such as individual dispersion and random loss). You can see it will be provided.

　　The neutral model adapts to the development trend. In short, with the development of zebrafish, ecological filters have become more and more important in the formation of intestinal flora. Based on these results, the researchers speculated that one of the methods for subjects to increase the filtration time of the gut microbial community is due to the maturity of the adaptive immune system. It is suspected that the presence of other fish may change the adaptive immune system's ability as an ecological filter, because host factors can spread microorganisms and host factors in the general environment. Have. Therefore, the researchers created a method of spreading between low or high potential wild-type and rag1 hosts by separating or mixing genotypes (Figure 1). It is assumed that increasing the transmission potential between the wild host and the rag1 host through the host's genotype will overwhelm the impact of adaptive immunity and make these communities more similar to the rag1 community. In order to determine whether adaptive immunity is an important ecological filter for the intestinal microbial community of adult zebrafish, the researchers found wild type (with adaptive immunity) and rag1- (adaptive immunity inactivation). We compared the host’s intestinal bacterial community and proposed four main hypotheses about the role of adaptive immunity as a filter:

　　(1) Adaptation through somatic rearrangement of B cell and T cell receptors. Immunization is personalized for the gut microbes of each host. The composition of wild and rag1 hosts is more different;

　　(2) The filtering effect of adaptive immunity makes the composition of wild and immunodeficient hosts very different

　　(3) Adaptive immunity can be used as a filter for microorganisms in the host environment, and it can produce a huge difference between the host environment water with immune system function and the intestinal microbial population. ;

　　(4) In the rag1 host, the lack of adaptive immunity plays a greater role in the assembly process and in the microbial community of the intestinal tissue.