A molecular analysis of NKT cells: identification of a class-I restricted T cell-associated molecule (CRTAM)

cDNA library subtraction techniques were used to identify transcripts expre ssed by activated mouse alpha beta TCR+ CD4(-)CD8(-) (double-negative; DN) T cells, a subset of natural killer T (NKT) cells. The most frequent cDNAs identified included the chemokines TCA3, macrophage inflammatory protein-1 alpha (MIP-1 alpha), MIP-1 beta, and lymphotactin (LPTN), the cytokines int erleukin-4 (IL-4) and interferon-gamma (IFN-gamma), and a granzyme, We also identified a new member of the immunoglobulin superfamily (Ig-SF), This mo lecule was designated class I-restricted T cell-associated molecule (CRTAM) as a result of its restricted expression pattern in T cells. Human CRTAM w as also identified, and shares the same expression pattern as the mouse mol ecule. LPTN and CRTAM exhibit the same expression pattern in T cells, sugge sting the existence of a gene expression program common to class I-MHC-rest ricted T cells.