Distinct responses of two hepatocellular carcinoma cell lines of a similar origin to immunotherapies targeting regulatory or effector T cells.

Balance between effector T cells (Teff) and regulatory T cells (Treg) appears to be very crucial for effective anti-tumor immunotherapy. The therapeutic efficacies of enhancement of Teff and suppression of Treg were compared between two murine hepatoma cell lines of a similar origin, MH129 and MH134. Enhancement of Teff was achieved by infection of tumor cells with adenovirus expressing glucocorticoid-induced tumor necrosis factor receptor-related protein (GITR), and suppression of Treg, by depletion of CD4+CD25+ naturally occurring Treg by administration of anti-CD25 monoclonal antibody (PC61) or low-dose cyclophosphamide.