Lack of Effect of Recombinant Human Interferon-α2b on Expression of 17-1A Antigen on Human Colon Cancer Cells

The effects of recombinant human interferon alpha (rHuIFN-α2b) on cell growth, expression of antigenic receptor sites (r) and the affinity constant (K_a) of monoclonal antibody CO 17-1A IgG were studied on two human colorectal cancer cell lines, CX-1 and SW 1116. Cells were incubated with varying concentrations of rHuIFN-α2b prior to exposure to ¹²⁵I-labeled 17-1A IgG at 37°C following which r and K_a were determined by means of Scatchard plots. Varying concentrations of rHuIFN-α2b had significant growth inhibitory effects on CX-1 and SW 1116 cells, which were time and concentration dependent, but no effects on expression of r and K_a compared to controls. Our data indicate that rHuIFN-α2b does not invariably increase the expression of tumor-associated antigens and that this effect may be independent of its antiproliferative activity. The in vitro response or lack thereof of neoplastic cells to rHuIFN-α2b may be useful to identify those patients who potentially might gain from a clinical course of rHuIFN-α2b for either therapeutic or diagnostic purposes.