Withdrawn CD1-MR1 2024

Synthetic 5-amino-6-D-ribitylaminouracil paired with inflammatory stimuli facilitates MAIT cell expansion in vivo (#225)

Adam G Nelson 1 , Huimeng Wang 1 2 , Phoebe M Dewar 1 , Eleanor M Eddy 1 , Songyi Li 1 , Xin Yi Lim 1 , Timothy Patton 1 3 , Yuchen Zhou 1 , Troi J Pediongco 1 , Lucy J Meehan 1 , Bronwyn S Meehan 1 , Jeffery YW Mak 4 , David P Fairlie 4 , Andrew W Stent 5 , Lars Kjer-Nielsen 1 , James McCluskey 1 , Sidonia BG Eckle 1 , Alexandra J Corbett 1 , Michael NT Souter 1 , Zhenjun Chen 1
  1. University of Melbourne, Melbourne, VICTORIA, Australia
  2. State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, Guangzhou Medical University, Guangzhou, China
  3. Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, Victoria, Australia
  4. Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
  5. Gribbles Veterinary Pathology, Clayton, Victoria, Australia

Mucosal-associated invariant T (MAIT) cells are a population of innate-like T cells, which mediate host immunity to microbial infection through recognition of metabolite antigens derived from microbial riboflavin synthesis presented by the MHC-I-related protein 1 (MR1). Namely, the potent MAIT cell antigens, 5-(2-oxopropylideneamino)-6-D-ribitylaminouracil (5-OP-RU) and 5-(2-oxoethylideneamino)-6-D-ribitylaminouracil (5-OE-RU), form via the condensation of the riboflavin precursor 5-amino-6-D-ribitylaminouracil (5-A-RU) with the reactive carbonyl species (RCS) methylglyoxal (MG) and glyoxal (G), respectively. Although MAIT cells are abundant in humans, they are rare in laboratory mouse strains, and increasing their abundance using expansion protocols with antigen and adjuvant has been shown to allow for effective study in mouse models of infection and disease. Here, we outline three methods to increase the abundance of MAIT cells in C57BL/6 mice using a combination of inflammatory stimuli, 5-A-RU and MG. Our data demonstrate that the administration of synthetic 5-A-RU in combination with one of three different inflammatory stimuli is sufficient to increase the frequency and absolute numbers of MAIT cells in C57BL/6 mice. The resultant boosted MAIT cells are functional and are shown to provide protection against a lethal infection of Legionella longbeachae. These results provide alternative methods for expanding functionally active MAIT cells with high doses of commercially available 5-A-RU (± MG) in the presence of various danger signals.