SELECTIVELY IMPAIRED DEVELOPMENT OF INTESTINAL T-CELL RECEPTOR GAMMA-DELTA(-CELL RECEPTOR ALPHA-BETA(+) CELLS IN T-CELL FACTOR-1-DEFICIENT MICE() CELLS AND LIVER CD4(+) NK1(+) T)

T cell factor-1 (Tcf-l) is a transcription factor that binds to a sequ ence motif present in several T cell-specific enhancer elements. In Tc f-1-deficient (Tcf-l(-)) mice. thymocyte development is partially bloc ked at the transition from the CD4(-)8(-) immature single-positive sta ge to the CD4(+)8(+) double-positive stage. resulting in a marked decr ease of mature peripheral T cells in lymph node and spleen. We report here that the development of most intestinal TCR gamma delta(.) cells and liver CD4(+)Nk1.l(+)TCR alpha beta (NKl(1)T) cells, which are beli eved to be of extrathymic origin. is selectively impaired in Tcf-l mic e. In contrast, thymic and thymus-derived (splenic) TCR gamma delta(+) cells are present in normal numbers in Tcf-l mice. as are other T cel l subsets in intestine and liver. Collectively. our data suggest that Tcf-l is differentially required for the development of some extrathym ic T cell subsets. including intestinal TCR gamma delta(+) cells and l iver CD4(+) NKl(+)T cells.