Effect of alpha-interferon on anti-alpha-fetoprotein-monoclonal-antibody targeting of hepatoma

We studied the potential of alpha-interferon (IFN-alpha) to enhance alpha-fetoprotein (AFP) and thus alter the localization of 125I-labeled antibody to the human hepatoma xenograft in athymic mice using monoclonal antibody (MAb) 19F12, which recognized AFP on the surface of human hepatoma cells. Treatment of the human hepatoma cell NuE with IFN-alpha increased the surface expression of AFP 2.4-fold in an IFN-dose-dependent manner. The IFN-alpha treatment substantially increased (2.7-fold) the localization of 125I-labeled 19F12 to NuE xenografts in athymic mice. The increase in localization of 125I-labeled 19F12 was dependent on the circulating plasma IFN levels. Our experimental results suggested that IFN-alpha could act as a potent modulator of the cellular antigen AFP, and be used to enhance the targeting of a conjugated MAb to hepatoma cell populations.