PROTECTION OF XENO-HEPATOCYTES FROM COMPLEMENT-MEDIATED CYTOLYSIS BY TRANSDUCTION WITH HOMOLOGOUS RESTRICTION FACTOR 20 GENE USING RETROVIRAL VECTOR

Xeno-hepatocyte transplantation has the possibility to substitute for clinical liver transplantation in certain restricted hepatic diseases such as inherited metabolic disorders, To overcome human complement-de pendent cytotoxicity on xeno-hepatocytes, the effectiveness of ex vivo transfer with the homologous restriction factor 20 (HRF20, CD59) gene was examined on primary-cultured xeno-hepatocytes using a retroviral vector, Primary-cultured rat hepatocytes transduced with HRF20 cDNA ex pressed HRF20 antigen by flowcytometric analysis and showed the integr ation of HRF20 cDNA to the genomic DNA by the polymerase chain reactio n. The viability of rat hepatocytes incubated with 50% human serum was decreased due to complement-dependent cytotoxicity, whereas that of t he transfectant was significantly protected (77.2 +/- 9.4 vs. 97.8 +/- 5.2%, p < 0.01). It was concluded that primary-cultured xeno-hepatocy tes transduced with HRF20 cDNA using a retroviral vector could escape complement-dependent cytolysis by human serum.