Arai K, Iiai T, Nakayama M, Hasegawa K, Sato K, Ohtsuka K, Watanabe H, Hanyu T, Takahashi H E, Abo T
Department of Immunology, Niigata University School of Medicine, Japan.
Immunology. 1995 Jan;84(1):64-71.
In addition to thymus-derived T cells, it was demonstrated recently that extrathymically differentiated T cells exist in the liver and other immune organs of mice. Since such extrathymic T cells have T-cell receptors (TCR) of intermediate intensity (i.e. intermediate TCR cells) and constitutively express IL-2 receptor beta-chain (IL-2R beta) similar to natural killer (NK) cells, they are easily distinguished from thymus-derived T cells with a TCR-bright+ IL-2R beta- phenotype (i.e. bright TCR cells). In the present study, the expression of adhesion molecules CD44 and L-selectin was compared between these T-cell subsets. Intermediate TCR cells in the liver and other organs were found to be CD44+ L-selectin- and, inversely, bright TCR cells were CD44- L-selectin+. CD3- IL-2R beta+ NK cells were also estimated to be CD44+ L-selectin-. Hyaluronic acid, which is known to adhere to a CD44 ligand, bound to intermediate TCR cells, but not to bright TCR cells. Among many extracellular matrices, hyaluronic acid induced a prominent decrease in the numbers and proportions of intermediate TCR cells and NK cells in the liver from 6 to 24 hr after in vivo administration. The half-life span of injected hyaluronic acid was approximately 7 hr in the plasma. These results suggest that the CD44 molecule, which is uniquely expressed on intermediate TCR cells and NK cells, is eventually associated with their adhesion to the sinusoidal walls in the liver.
除了胸腺来源的T细胞外，最近还证明，在小鼠的肝脏和其他免疫器官中存在胸腺外分化的T细胞。由于这种胸腺外T细胞具有中等强度的T细胞受体（TCR）（即中等TCR细胞），并组成性地表达与自然杀伤（NK）细胞相似的白细胞介素2受体β链（IL-2Rβ），因此它们很容易与具有TCR亮+ IL-2Rβ-表型的胸腺来源的T细胞（即亮TCR细胞）区分开来。在本研究中，比较了这些T细胞亚群之间黏附分子CD44和L-选择素的表达。发现肝脏和其他器官中的中等TCR细胞为CD44+ L-选择素-，相反，亮TCR细胞为CD44- L-选择素+。CD3- IL-2Rβ+ NK细胞也被估计为CD44+ L-选择素-。已知与CD44配体结合的透明质酸与中等TCR细胞结合，但不与亮TCR细胞结合。在许多细胞外基质中，透明质酸在体内给药后6至24小时内导致肝脏中中等TCR细胞和NK细胞的数量和比例显著下降。注射的透明质酸在血浆中的半衰期约为7小时。这些结果表明，在中等TCR细胞和NK细胞上独特表达的CD44分子最终与其在肝脏中与窦壁的黏附有关。
