Researchers at the Peter Doherty Institute for Infection and Immunity made a fundamental discovery about how Mucosal-associated invariant T (MAIT) cells function, especially in the context of protective immunity.

“Our finding that CD8 binds MHC class I (MHC-I) related protein 1 (MR1) fills a knowledge gap in the fundamental biology of MAIT and other MR1-reactive T cells,” says University of Melbourne Dr Michael Souter, Immunologist at the Doherty Institute.

“This interaction is likely an integral part of the protective immune function of MAIT cells in microbial infections and maybe cancer, enhancing MR1 recognition and broadening the repertoire of MR1-bound antigens that can be cross-recognised (an active area of research in the field).”

“The CD8-MR1 interaction may also drive autoreactivity and cross-reactivity with pathological consequences, which may lead to autoimmune or allergic reactions,” explains University of Melbourne Dr Sidonia Eckle, Immunologist and Group Leader of the MAIT Cell Program at the Doherty Institute.

“It has been recognised that MAIT and other MR1-reactive T cells combine a number of features that render them suitable targets for immunotherapies. However, this is still an emerging area of research and a complete understanding of how exactly they function is needed in order to harness them therapeutically,” says Dr Eckle.

“Our study, delineating the function of CD8 coreceptor expressed by most MAIT and other MR1-reactive T cells, provides an important piece to this puzzle.”

The study, ‘CD8 coreceptor engagement of MR1 enhances antigen responsiveness by human MAIT and other MR1-reactive T cells’, is published in Journal of Experimental Medicine.

This article was adapted from an original article by the Peter Doherty Institute for Infection and Immunity.