Variation of surface antigen expression is a mechanism used by microbes to adapt to and persist within their host habitats. Helicobacter pylori, a persistent bacterial colonizer of the human stomach, can alter its surface Lewis (Le) antigen expression. We examined H. pylori colonization in mice to test the hypothesis that host phenotype selects for H. pylori (Le) phenotypes. When wild-type and Leb-expressing transgenic FVB/N mice were challenged with H. pylori strain HP1, expressing Lex and Ley, we found that bacterial populations recovered after 8 mo from Leb-transgenic, but not wild-type, mice expressed Leb. Changes in Le phenotype were linked to variation of a putative galactosyltransferase gene (β-(1,3)galT); mutagenesis and complementation revealed its essential role in type I antigen expression. These studies indicate that H. pylori evolves to resemble the host's gastric Le phenotype, and reveal a bacterial genetic locus that is subject to host-driven selection pressure.
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机译:表面抗原表达的变化是微生物用来适应并在其宿主生境中持续存在的机制。幽门螺杆菌(Helicobacter pylori)是人胃的持久细菌定居者,可以改变其表面路易斯(Le)抗原表达。我们检查了小鼠中的幽门螺杆菌定植,以检验宿主表型选择幽门螺杆菌(Le)表型的假说。当野生型和表达Le b sup>的转基因FVB / N小鼠被幽门螺杆菌HP1攻击时,表达Le x sup>和Le y sup> ,我们发现8个月后从Le b sup>转基因小鼠(而非野生型)中表达Le b sup>的细菌种群恢复了。 Le表型的变化与假定的半乳糖基转移酶基因(β-(1,3)galT)的变化有关;诱变和互补揭示了其在I型抗原表达中的重要作用。这些研究表明幽门螺杆菌进化成类似于宿主的胃Le表型,并揭示了受宿主驱动的选择压力的细菌遗传基因座。
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