小鼠胸腺上皮细胞株MTEC_B与胸腺细胞结合的形态学观察

MORPHOLOGICAL OBSERVATION OF THYMIC EPITHELIAL CELL LINE (MTECB) BINDING WITH THYMOCYTES

用本室建立的小鼠胸腺上皮细胞株MTEC_B,分别在1.无钙镁Hank液中(4℃);2.无钙镁Hank液中(37℃);3.含钙镁Hank液中(4℃)下;4.含钙镁Hank液中(37℃)与胸腺细胞共育(基质细胞:胸腺细胞=1:10),光镜和扫描电镜下观察:它们之间的结合特点。发现在各种实验条件下,90％的MTEC_B能与胸腺细胞结合,这种结合从形态上分为两种形式,其一为胸腺细胞均匀结合于MTEC_B周围,呈花环样,其二为胸腺细胞集中结合于MTEC_B的一侧,呈簇状。统计结果表明,这些结合不依赖钙镁离子,也不依赖温度,4℃和37℃的结合率无明显差异。同种异型的胸腺细胞与MTEC_B的结合率也没有明显差异,说明这种结合的介导分子不是MHC分子,介导这种结合的粘附分子可能为CD2/FA-3。

MTECB were cultured on the glass coverslips at an initial concentration 5.0×104cells/ml in the DME containing 10% NCS. After 3 days,the coverslips were washed with Hank medium to remove the serum and the thymocytes were added to the coverslips on which MTECs adhered. After 2.5 hours coculture in Hank medium at different conditions : 1. at 4℃ in the absence of Ca2+ and Mg2+ ;2. at 4℃ in the presence of Ca2+ and Mg2+ ;3. at 37℃ in the absence of Ca2+ and Mg2+ ; 4. at 37℃ in the presence of Ca2+ and Mg2+ , the binding efficiency was analyzed. In the various conditions, 90% MTECB has the ability of binding with thymocytes. The forms of thymocytes binding with MTECB are divided into two distinct groups under scanning electron microscope. One is thymocytes binding around MTECB,another is thymocytes in masses concentrating on a certain side of MTECB. According to the statistical results,the binding capacity neither depends upon the temperature nor depends upon the presence of Ca2+ and Mg2+. Additionally,MTECB has the same binding capacity with H-2b thymocytes as with H-2d thymocytes. All results above indicate that MHC molecules don't participate in the binding process between thymocytes and MTECB,CD2/ LFA-3 molecules might intermediated the binding process.