Comparison of effects of CH50 on macrophage activation and its anti-tumor activity with those of lipopolysaccharides

AIM: To investigate the characterization of pharmacological action & of CH50, a recombinant polypeptide of human fibronectin, by comparing the effects of CH50 on macrophage activation and its anti-tumor activity with those of lipopolysaccharides (LPS). METHODS: The production of nitric oxide (NO) as an index macrophage activation was determined by colorimetric assay. The interferon-gamma (IFN-gamma) transfection was performed with coprecipitation of calcium phosphate and DNA. The melanoma B16 cells were inoculated into abdominal cavity of mice and the number of tumor nodes was recorded. RESULTS: At lower concentrations or when given alone in vitro, CH50 produced ten times less NO than LPS (P < 0.01). But at concentrations higher than 1 mg.L-1, CH50 activated the IFN-gamma-primed macrophages to produce NO to the same extent as LPS (P > 0.05). There was no synergism between CH50 and LPS. Both CH50 and LPS alone could reduce the number of tumor nodes in abdominal cavity of mice but CH50 had a stronger inhibitory effect on the growth of tumor in vivo as compared to LPS (P < 0.01). CH50/IFN-gamma had also a better inhibitory effect on tumor growth in vivo than LPS/IFN-gamma did. CONCLUSION: In the presence of IFN-gamma, the ability of CH50 to activate macrophages is the same as that of LPS. But CH50 has better antitumorogenic effects in vivo against mouse melanoma as compared to LPS.