MAIT cells protect against fatal pulmonary infection by <em>Legionella </em>species via IFNg and can be augmented by synthetic ligands. — ASN Events
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  3. MAIT cells protect against fatal pulmonary infection by Legionella species via IFNg and can be augmented by synthetic ligands.

MAIT cells protect against fatal pulmonary infection by Legionella species via IFNg and can be augmented by synthetic ligands. (#81)

Huimeng Wang 1 , Criselle D'Souza 1 , Xin Yi Lim 1 , Lyudmila Kostenko 1 , Troi Pediongco 1 , Sidonia Eckle 1 , Bronwyn Meehan 1 , Nancy Wang 1 , Ligong Liu 2 , Jeffrey Mak 2 , David Fairlie 2 , Yoichiro Iwakura 3 , Jenny Gunnersen 1 , Andrew Stent 1 , Jamie Rossjohn 4 5 , Glen Westall 6 , Lars Kjer-Nielsen 1 , Richard Strugnell 1 , James McCluskey 1 , Alexandra Corbett 1 , Timothy Hinks 1 7 , Zhenjun Chen 1
  1. University of Melbourne, Melbourne, VIC, Australia
  2. The University of Queensland, Brisbane, Australia
  3. Tokyo University of Science, Tokyo, Japan
  4. Monash University, Melbourne, Australia
  5. Cardiff University, Cardiff, UK
  6. Alfred Hospital, Melbourne, Australia
  7. University of Oxford, Oxford, UK

Mucosal Associated Invariant T (MAIT) cells are an abundant subset of immune cells. MAIT cells are found to recognize metabolites derived from bacterial riboflavin synthesis presented by MHC-related 1 (MR1) molecule, which suggests that they play a critical role in immunity against bacterial infections. By using a murine pulmonary infection model with Legionella longbeachae, we found MAIT cells accumulated robustly at the site of infection and produced several critical cytokines to control the infection, including IFN-g, GM-CSF and IL-17A. We were able to show for the first time with a clinically relevant human pathogen that MAIT cells contributed to bacterial clearance in wild type mice and this protection role became more apparent in the absence of CD4+ T cells. Notably, adoptively transferred MAIT cells provide Rag2GammaC knockout mice with full protection against lethal Legionella infection in an IFN-g dependent manner. These findings suggest that MAIT cells are important to control Legionella longbeachae; a finding of potentially wider relevance to other intracellular infections.