OBJECTIVES: To study the interaction of beta-2-glycoprotein I (beta 2GPI) with the membrane of hepatocytes and determine whether beta 2GPI participates in HBV infection. METHODS: Ligand blotting, fluorescence microscopy, and fluorescence activated cell sorter (FACS) analysis were used to detect the specific interaction of beta 2GPI with the hepatoma cell line smmc7721, the gastric carcinoma cell line SGC7901, and the lymphoma cell line HL-60. RESULTS: A specific 40 kDa beta 2GPI band was observed by ligand blotting in the case of smmc7721 cells. No such band was observed in SGC7901 or HL-60 cells. Fluorescence microscopy also revealed specific binding of FITC-beta 2GPI to smmc7721 cells, but neither to SGC7901 nor HL-60 cells. FACS analysis demonstrated that the binding rate of FITC-beta 2GPI to smmc7721 cells was significantly higher than these in SGC7901 and HL-60 cells (P < 0.01). The binding rate to smmc7721 cells did not increase with increasing amounts of FITC-beta 2GPI. CONCLUSIONS: There is a specific beta 2GPI-binding protein on the membrane of hepatoma cells in cell line smmc7721 which as the beta 2GPI receptor may participate in HBV infection of hepatocytes.
OBJECTIVES: To study the interaction of beta-2-glycoprotein I (beta 2GPI) with the membrane of hepatocytes and determine whether beta 2GPI participates in HBV infection. METHODS: Ligand blotting, fluorescence microscopy, and fluorescence activated cell sorter (FACS) analysis were used to detect the specific interaction of beta 2GPI with the hepatoma cell line smmc7721, the gastric carcinoma cell line SGC7901, and the lymphoma cell line HL-60. RESULTS: A specific 40 kDa beta 2GPI band was observed by ligand blotting in the case of smmc7721 cells. No such band was observed in SGC7901 or HL-60 cells. Fluorescence microscopy also revealed specific binding of FITC-beta 2GPI to smmc7721 cells, but neither to SGC7901 nor HL-60 cells. FACS analysis demonstrated that the binding rate of FITC-beta 2GPI to smmc7721 cells was significantly higher than these in SGC7901 and HL-60 cells (P < 0.01). The binding rate to smmc7721 cells did not increase with increasing amounts of FITC-beta 2GPI. CONCLUSIONS: There is a specific beta 2GPI-binding protein on the membrane of hepatoma cells in cell line smmc7721 which as the beta 2GPI receptor may participate in HBV infection of hepatocytes.