Host Selection of Microbiota via Differential Adhesion

• Adhesive molecules produced by a host can select for specific microbes
• Selective adhesion can maintain even disadvantaged microbes through refugia creation
• Changes in mucus flow, with adhesion, can select for and against specific microbes
• Candidate molecules for this function are mucus glycans and immunoglobulin A

SummaryThe host epithelium is the critical interface with microbial communities, but the mechanisms by which the host regulates these communities are poorly understood. Here we develop the hypothesis that hosts use differential adhesion to select for and against particular members of their microbiota. We use an established computational, individual-based model to study the impact of host factors that regulate adhesion at the epithelial surface. Our simulations predict that host-mediated adhesion can increase the competitive advantage of microbes and create ecological refugia for slow-growing species. We show how positive selection via adhesion can be transformed into negative selection if the host secretes large quantities of a matrix such as mucus. Our work predicts that adhesion is a powerful mechanism for both positive and negative selection within the microbiota. We discuss molecules—mucus glycans and IgA—that affect microbe adhesion and identify testable predictions of the adhesion-as-selection model.

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