Antimetastatic and growth-inhibitory effects of N-acetylchitohexaose in mice bearing Lewis lung carcinoma.

N-Acetylchitohexaose, a water-soluble oligosaccharide was found to display a significant antimetastatic effect against Lewis lung carcinoma (LLC) transplanted into C57BL/6 mice, giving rise to a 40-50% inhibition ratio of pulmonary metastasis when administered intravenously (1 mg/kg) on day 6 after the tumor implantation (5 x 10(5) cells/mouse). It was also revealed that this hexaose had a significant growth-inhibitory effect against the local tumor of the same carcinoma (a 20-30% inhibition ratio), showing an enhancing effect on concomitant immunity in local tumor-resected mice. This oligosaccharide was also shown to enhance the tumoricidal effect of splenic T lymphocytes against LLC and P-815 mastocytoma cells and to increase the natural killer activity of splenic T lymphocytes, assayed with YAC-1 cells as the target.