CD1A and infection: Moreover, group 1 CD1-restricted Mtb lipid-specific T cells are found in higher frequencies in individuals exposed to Mtb compared with control populations, suggesting that they are activated following infection with Mtb (Moody, 2000; Ulrichs et al., 2003; Gilleron, 2004; Layre et al., 2009; Moody et al., 2000).