THE ROLE OF MAIT CELL IN PROTECTION AGAINST INFECTION IN-VIVO

Abstract

MAIT cells are also activated during human viral infections, yet it remains unknown whether MAIT cells play a significant protective or even detrimental role during viral infections in vivo. Using murine experimental challenge with two strains of influenza A virus, we show that MAIT cells accumulated and were activated early in infection, with upregulation of CD25, CD69 and Granzyme B, peaking at 5 days post infection. Activation was modulated via cytokines independently of MR1. MAIT cell-deficient MR1-/- mice showed enhanced weight loss and mortality to severe (H1N1) influenza. This was ameliorated by prior adoptive transfer of pulmonary MAIT cells in both immunocompetent and immunodeficient RAG2-/-gC-/- mice. Thus, MAIT cells contribute to protection during respiratory viral infections, and constitute a potential target for therapeutic manipulation.

Key words: Mucosal associated invariant T cell, T cell, infection, influenza virus.