RELATIONSHIPS BETWEEN INTERMEDIATE TCR CELLS AND NK1.1(-CELLS IN VARIOUS IMMUNE ORGANS - NK1.1(+) T-CELLS ARE PRESENT WITHIN A POPULATION OF INTERMEDIATE TCR CELLS() T)

Experiments to date have revealed a population of T cells that carry i ntermediate (int) levels of TCR (or CD3) and express IL-2R beta-chain (IL-2R beta) in mouse liver. Such int TCR cells also reside in other i mmune organs, although in low numbers. On the other hand, NK1.1(+) T c ells with int TCR do reside in the thymus and other peripheral organs. To determine the relationship of two types of cells, we characterized int CD3 cells and NK1.1(+) T cells throughout the organs in terms of the phenotype, V beta repertoire, and morphology. Although both IL-2R beta(+) T cells and NK1.1(+) T cells are classified as int CD3 cells, NK1.1(+) T cells are present within int CD3 cells. The majority of int CD3 cells in the liver and thymus were NK1.1(+), whereas the minority of such cells in the spleen, lymph nodes, and bone marrow were NK1.1( +). Among int CD3 cells, double-negative (DN) CD4(-)8(-) cells and/or CD4(+) were abundant in NK1.1(+) subset, whereas CD8(+) cells were gen erally abundant in NK1.1(-) subset. Self-reactive V beta(+) clones est imated by the M1s system were distributed to both NK1.1(+) and NK1.1(- ) subsets. High CD3 cells in the thymus and other organs contained nei ther DN cells nor forbidden clones. Int CD3 cells had the morphology o f granular or agranular lymphocytes carrying perforin. Among int CD3 c ells, NK1.1(+) subset had a higher level of perforin-positive cells th an NK1.1(-) subset. These results clearly demonstrate the relationship between int TCR cells and NK1.1(+) T cells in various organs.