Microbiota regulates immune defense against respiratory tract influenza A virus infection

Takeshi Ichinohe et al.( 2011). Proc Natl Acad Sci U S A 108, 5354-5359.

Speaker: Chan-Yi Su (蘇展儀)                      Time: 14:00~ 15:00, Dec. 28, 2011

Commentator: Lien-I Hor (何漣漪老師)     Place: Room 601

Abstract

Influenza virus is the major source of severe viral respiratory infections, causing epidemics that result in severe morbidity and mortality annually. Commensal bacteria provide mammalian hosts with essential functions in the digestive system. Although their importance in the maintenance of immune homeostasis in the gut mucosa is widely appreciated, it remains unclear whether there is a role for microbiota in shaping the immune inductive functions at a nonintestinal mucosa surface such as the lung. In this study, the authors used antibiotic treated mice to investigate the role ofcommensal microbiota in the immune response to influenza virus. They found that local or distal injection of Toll-like receptor (TLR) ligands could rescue the immune impairment in the antibiotic-treated mice. Further, they analysed the responsible bacteria classes and found that neomycin-sensitive bacteria are associated with the induction of productive immune responses in the lung. Miocrobiota provided signals leading to the expression of mRNA for pro-IL-1β and pro-IL-18 at steady state. Following influenza virus infection, inflammasome activation led to migration of dendriticcells (DCs) from the lung to the draining lymph node and T-cell priming. In summary, this study revealed that the commensal microbiota could regulate the immune response in the respiratory mucosa through the proper activation of the inflammasome.

References

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2.      Willing, B.P., Russell, S.L., and Finlay, B.B. (2011). Shifting the balance: antibiotic effects on host-microbiota mutualism. Nat Rev Microbiol 9, 233-243.