Gut immune maturation depends on colonization with a host-specific microbiota.
Gut microbial induction of host immune maturation exemplifies host-microbe mutualism. We colonized germ-free (GF) mice with mouse microbiota (MMb) or human microbiota (HMb) to determine whether small intestinal immune maturation depends on a coevolved host-specific microbiota. Gut bacterial numbers and phylum abundance were similar in MMb and HMb mice, but bacterial species differed, especially the Firmicutes. HMb mouse intestines had low levels of CD4(+) and CD8(+) T cells, few proliferating T cells, few dendritic cells, and low antimicrobial peptide expression--all characteristics of GF mice. Rat microbiota also failed to fully expand intestinal T cell numbers in mice. Colonizing GF or HMb mice with mouse-segmented filamentous bacteria (SFB) partially restored T cell numbers, suggesting that SFB and other MMb organisms are required for full immune maturation in mice. Importantly, MMb conferred better protection against Salmonella infection than HMb. A host-specific microbiota appears to be critical for a healthy immune system.
Channing Laboratory, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
Hachung
H
Chung
Sünje J
SJ
Pamp
Jonathan A
JA
Hill
Neeraj K
NK
Surana
Sanna M
SM
Edelman
Erin B
EB
Troy
Nicola C
NC
Reading
Eduardo J
EJ
Villablanca
Sen
S
Wang
Jorge R
JR
Mora
Yoshinori
Y
Umesaki
Diane
D
Mathis
Christophe
C
Benoist
David A
DA
Relman
Dennis L
DL
Kasper
D000818:Animals; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000378:metabolism; D049109:Cell Proliferation; D005260:Female; D005856:Germ-Free Life; D006801:Humans; D007113:Immunity, Innate; D007422:Intestines / Q000276:immunology* / Q000382:microbiology*; D008297:Male; D054892:Metagenome; D051379:Mice; D051381:Rats; D017207:Rats, Sprague-Dawley; D012480:Salmonella Infections / Q000276:immunology; D013045:Species Specificity; D013047:Specific Pathogen-Free Organisms; D013559:Symbiosis; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology