Murine CD1d-restricted T cell recognition of cellular lipids

NKT cells are associated with immunological control of autoimmune disease a nd cancer and can recognize cell surface mCD1d without addition of exogenou s antigens. Cellular antigens presented by mCD1d have not been identified, although NKT cells can recognize a synthetic glycolipid, alpha-GalCer. Here we show that after addition of a lipid extract from a tumor cell line, pla te-bound mCD1d molecules stimulated an NKT cell hybridoma. This hybridoma a lso responded strongly to three purified phospholipids, but failed to recog nize alpha-GalCer. Seven of sixteen other mCD1d restricted hybridomas also showed a response to certain purified phospholipids. These findings suggest NKT cells can recognize cellular antigens distinct from alpha-GalCer and i dentify phospholipids as potential self-antigens presented by mCD1d.