One of the chief requirements of an immune system, the mucosal immune system, that lies
juxtaposed to a mass of potentially immunogenic commensal organisms is a well-developed
mechanism to limit or negatively regulate nascent immune responses to those organisms.
This mechanism, long subsumed under the name oral tolerance, is now understood to
consist of a complex of factors, not the least of which is the ready ability to induce
immunosuppressive regulatory T cells or Tregs. The emphasis here is on the “ability to …