Segmented filamentous bacteria, partners in intestinal immunity, finally cultured in vitro

Segmented filamentous bacteria, partners in intestinal immunity, finally cultured in vitro

 

Segmented filamentous bacteria (SFB) are bacteria from the Clostridiaceae family that colonize the intestines of many species, likely including humans, without causing disease; studies in mice have shown that they live in symbiosis with epithelial cells and are involved in the maturation of intestinal immunity.

Despite the vital role of SFB in establishing gut immune homeostasis, scientists, for the past 50 years, have been unable to reproduce this symbiosis in vitro to shed light on the cellular and molecular interactions involved. Now, INSERM scientists from Institut Pasteur and Institut Imagine have successfully cultured and reproduced the complex life-cycle of these bacteria outside their host for the first time.

A closer look at the symbiosis between SFB and their host

 

A single-celled intracellular offspring form of these bacteria attach themselves directly to intestinal epithelial cells, creating a mutually beneficial interaction between the bacteria and the host.

This non-pathogenic yet intimate relationship, which is established immediately after weaning, provides the bacteria with nutrients and, in turn, stimulates the development and maturation of the intestinal immune system. The delicate balance between these bacteria and their host protects the host from pathogens by strengthening both the epithelial barrier and the immune system. Animals lacking segmented filamentous bacteria in their intestinal flora are more susceptible to infection, even in adulthood.

The reproduction of this complex system in vitro should finally enable scientists to decode the dialog between the host and the bacteria and also to shed light on the way in which antibiotics can disrupt immune development as antibiotics lead to SFB disappearance from the gut.

 

Illustration: © Institut Pasteur and Institut Imagine

 

Source

 

Growth and host interaction of mouse Segmented Filamentous Bacteria in vitro, Nature, January 19, 2015

Pamela Schnupf1,3, Valérie Gaboriau-Routhiau3,4,5, Marine Gros5,6, Robin Friedman1, Maryse Moya-Nilges2, Giulia Nigro1, Nadine Cerf-Bensussan3,5*, Philippe Sansonetti1,7*

 

1Molecular Microbial Pathogenesis Unit, INSERM, U786

2Imagopole, Ultrastructural Microscopy Platform, Institut Pasteur, 25–28 Rue du Dr Roux, 75724 Paris Cedex 15, France

3INSERM, UMR1163, Laboratory of Intestinal Immunity

4INRA Micalis UMR1319, 78350 Jouy-en-Josas, France

5Paris Descartes-Sorbonne Paris Cité University and Imagine Institute, 75015 Paris, France

6Ecole Normale Supérieure de Lyon, 69007 Lyon, France

7Microbiology and Infectious Diseases, Collège de France, Paris, France

* Contributed equally