Expression of BCL-2 in hepatic antigen-presenting cells during viral hepatitis induced by SV40 large T antigen gene transfer in the liver.

We developped a gene transfer method in order to express SV40 large T antigen (Tag) in the rat liver. Tag-transfected hepatocytes were stained positively in immunohistochemistry. After several days, lymphocytes infiltration in the liver was observed. Transfected-hepatocyte apoptosis followed the lymphocyte infiltration. A TUNEL assay revealed therefore an increase in the number of hepatocyte apoptosis in the liver.

We observed that according to the antigen-presenting cell (APC) model, hepatic APC expressed BCL-2 by immunohistochemistry after Tag gene transfer. This BCL-2 expression was observed a few days before lymphocyte infiltration and hepatocyte apoptosis.

This observation could be explained as an activation of liver APC, in order to induce hepatic infiltration by lymphocytes.

We also found soluble liver antigen antibodies in the serum. The soluble antibodies were identical to LP2 antibodies as observed in autoimmune hepatitis. Sera were negative for antinuclear antibodies and anti-LKM ( liver-kidney-microsome) antibodies.

In conclusion, liver APC expressed BCL-2 before lymphocyte infiltration and Tag-transfected hepatocyte apoptosis in the viral hepatitis.