Article

The Key Role of Segmented Filamentous Bacteria in the Coordinated Maturation of Gut Helper T Cell Responses

INRA, U910, Unité Ecologie et Physiologie du Système Digestif, Domaine de Vilvert, 78350 Jouy-en-Josas, France.
Immunity (Impact Factor: 19.75). 10/2009; 31(4):677-89. DOI: 10.1016/j.immuni.2009.08.020
Source: PubMed

ABSTRACT Microbiota-induced cytokine responses participate in gut homeostasis, but the cytokine balance at steady-state and the role of individual bacterial species in setting the balance remain elusive. Herein, systematic analysis of gnotobiotic mice indicated that colonization by a whole mouse microbiota orchestrated a broad spectrum of proinflammatory T helper 1 (Th1), Th17, and regulatory T cell responses whereas most tested complex microbiota and individual bacteria failed to efficiently stimulate intestinal T cell responses. This function appeared the prerogative of a restricted number of bacteria, the prototype of which is the segmented filamentous bacterium, a nonculturable Clostridia-related species, which could largely recapitulate the coordinated maturation of T cell responses induced by the whole mouse microbiota. This bacterium, already known as a potent inducer of mucosal IgA, likely plays a unique role in the postnatal maturation of gut immune functions. Changes in the infant flora may thus influence the development of host immune responses.

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