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 anti‐metastatic 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 × 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.