MAIT cell activation augments adenovirus vector vaccine immunogenicity
Provine NM., Amini A., Garner LC., Spencer AJ., Dold C., Hutchings C., Silva Reyes L., FitzPatrick MEB., Chinnakannan S., Oguti B., Raymond M., Ulaszewska M., Troise F., Sharpe H., Morgan SB., Hinks TSC., Lambe T., Capone S., Folgori A., Barnes E., Rollier CS., Pollard AJ., Klenerman P.
Vaccines get a help-MAIT Mucosal-associated invariant T (MAIT) cells are a T cell subset important for mucosal homeostasis. These cells recognize derivatives of microbiota-derived vitamin B2 precursors but can also be activated by certain cytokines in the context of viral infections. Provine et al. report that a leading adenoviral vector vaccine, ChAdOx1, activated MAIT cells in immunized mice (see the Perspective by Juno and O'Connor). This activation required interferon-α produced by plasmacytoid dendritic cells as well as monocyte-derived interleukin-18 and tumor necrosis factor. MAIT cell activation positively correlated with vaccine-mediated T cell responses in human subjects, and mice deficient in MAIT cells showed impaired CD8 + T cell immunity to target antigens after vaccination. This work suggests an additional pathway that could be exploited to enhance the efficacy of vaccines. Science , this issue p. 521 ; see also p. 460