INHIBITION OF ESTABLISHMENT AND GROWTH OF MOUSE-LIVER METASTASES AFTER TREATMENT WITH INTERFERON-GAMMA AND BETA-1,3-D-GLUCAN

The purpose of this study was to investigate the combined antitumor ef fect of aminated beta-1,3-D-glucan (AG) and interferon-gamma (IFN-gamm a) in an experimental liver metastasis model. Liver metastases were es tablished by inoculation of C-26 colon carcinoma cells into the superi or mesenteric vein of syngeneic mice. Treatment of mice started 24 hou rs after inoculation of tumor cells by daily intravenous injections of either AG, IFN-gamma, or a combination of both for a duration of 6 da ys. The resultant liver metastases were then quantified after an addit ional period of 11 days. Combination of IFN-gamma and AG inhibited the growth of liver metastases almost entirely. IFN-gamma was also very e fficient, while AG alone did not exert any significant antitumor effec t. These results, along with histological studies from mice receiving AG and IFN-gamma, indicated that activation and recruitment of liver m acrophages may be a part of the mechanism responsible for the inhibiti on of metastatic growth observed in this study.