Abstract
Microcytotoxicity assay revealed that peripheral blood lymphocytes from patients with chronic active hepatitis were cytotoxic against cultured rat liver cells established by Coon in 1968. Non E-rosette forming cells were cytotoxic in 26 of 28 patients (93%) with chronic active hepatitis, whereas E-rosette forming cells were cytotoxic in only 1 of them. Either an addition of 10μg/well of aggregated IgG to non E-rosette forming cell culture or a preincuba-tion of non E-rosette forming cells with 100μg/ml of aggregated IgG significantly reduced the cytotoxicity from 62.9±12.8% to 32.8±11.6% or to 25.6±11.3% (p<0.001). An addition of antihuman IgG/Fc also reduced the cytotoxicity to 37.4±17.2%. Significant cytotoxicity of positively selected EA-rosette forming cells was observed in 4 of 10 patients with chronic active hepatitis and that of positively selected EAC-rosette forming cells was demonstrated in 3, whereas in any of these patients neither non EA-rosette forming cells nor non EAC-rosette forming cells were cytotoxic. Cultured liver cells used in this study were seen to possess insoluble liver specific antigen on their surface membranes, but not soluble liver specific lipoprotein of Meyer zum Biischenfelde, by using an indirect immunofluorescence technique. These results suggested that effector cells are Fcreceptor-bearing cells and that the mechanism of the reaction may be mediated in an antibody-dependent cell-mediated reaction directed against insoluble liver specific membrane antigen(s) rather than soluble one.
