MAIT cell responses to infection comprise a range of functions from secretion of IFNɣ, TNF and IL-17 (Gold et al. 2010; Le Bourhis et al. 2010), to cytotoxicity via perforin, granzyme B (GzmB) and granulysin (Boulouis et al. 2020a, b; Kurioka et al. 2015; Le Bourhis et al. 2013), and potentially to tissue repair (Constantinides et al. 2019; Hinks et al. 2019; Lamichhane et al. 2019; Leng et al. 2019). Here, GZMB is linked to infection.