摘要：SummaryBats are reservoirs for a large number of viruses which have potential to cause major human disease outbreaks, including the current coronavirus disease 2019 (COVID-19) pandemic. Major efforts are underway to understand bat immune response to viruses, whereas much less is known about their immune responses to bacteria. In this study, MR1-restricted T (MR1T) cells were detected through the use of MR1 tetramers in circulation and tissues ofPteropus alecto(Pa) bats. Pa MR1T cells exhibited weak responses to MR1-presented microbial metabolites at resting state. However, following priming with MR1-presented agonist they proliferated, upregulated critical transcription factors and cytolytic proteins, and gained transient expression of Th1/17-related cytokines and antibacterial cytotoxicity. Collectively, these findings show that the Pa bat immune system encompasses an abundant and functionally conserved population of MR1T cells with mucosal-associated invariant T-like characteristics, suggesting that MR1 and MR1T cells also play a significant role in bat immune defense.Graphical AbstractDisplay OmittedHighlights•MR1T cells are present in Pa bats and react to MR1-presented microbial metabolites•Pa MR1T cells upregulate Prf and MAIT-associated TFs upon culture with MR1 agonists•Upon stimulation, Pa MR1T cells rapidly and transiently express TNF and IL-17•Pa MR1T cells killE. coliand MR1 agonist-pulsed cells in an MR1-dependent mannerBiological Sciences; Immunology; Components of the Immune Systems
