Recent results strengthen evidence that CD1-restricted T cells play importa
nt roles in host defense against microbial infections. Human subjects recen
tly infected with Mycobacterium tuberculosis showed elevated responses to C
D1c-mediated presentation of a microbial lipid antigen, compared with contr
ol donors. Activation of CD1d-restricted NKT cells with a synthetic glycoli
pid antigen results in improved immune responses to several infectious path
ogens.