[Internalization of monoclonal antibodies against human hepatoma in the target cells]

The monoclonal antibodies against human hepatoma, HAb23, HAb18 and HAb8, were linked with 5 nm colloid gold. They were used to incubate with the target cells, QGY-7703 and SMMC-7721 human hepatoma cell lines, at 4 degree C for 1 hour. The incubated hepatoma cells were divided into 6 groups and then were put into 37 degree C water incubator for 0, 5, 10, 30, 60 and 120 minutes respectively. After washing, the target cells were fixed with Karnovsky's fixative and embedded in Epon 812. There were four intracellular routings for HAb 23, HAb18 and HAb8 to enter the QGY-7703 and SMMC-7721 hepatoma cells: (1) Coated pits coated: The colloid gold-antibodies which clustered in the specialised regions of the surface membrane were invaginated rapidly into the cells to form coated vesicles. (2) Enclosed invagination: One or two colloid gold-antibodies which were attached on the surface membrane were invaginated into the cell by endocytosis. (3) Microvilli involved routing: The microvilli which were adsorbed by the colloid gold-antibodies were broken and then were phagocytized by the cells. (4) Routing via glycocalyx-like material: The glycocalyx-like material which was clustered by the colloid gold-antibodies was invaginated during endocytosis.