Antitumor effects of Eubacterium lentum fractions and its correlation with the macrophages, natural killer activities in mice

Abstract

The present study was undertaken to examine the effects of cell fractions of Eubacterium lentum, especially cell wall and fraction 2 (cytoplasmic membrane) on Ehrlich ascites tumor bearing mice. All fractions except cell wall and fraction 2 did not effectively inhibit the Ehrlich ascites tumor growth in ICR mice. Intratumoral injection of cell wall of Eubacterium lentum at a dose of at least 100 μg significantly inhibited the tumor growth 21 days after tumor inoculating and prolonged the survival time of mice. Intravenous injection of cell wall at a dose of at least 200 μg was effective in prolonging the survival time of tumor-bearing mice. Moreover, the effects of intraperitoneal treatment by cell wall or fraction 2 of Eubacterium lentum on macrophage activities of peritoneal exudate cavity (PEC) cells was examined. The results obtained showed that both cell wall and fraction 2 have the ability to enhance the peritoneal macrophage activity in Balb/c mice. Furthermore, cell mediated cytotoxicity at single cell levels against YAC-1 lymphoma as target cell when treated with cell wall or fraction 2 and the kinetics of natural killer (NK) activity of spleen cells were observed. These results suggest that both cell wall and fraction 2 are potent activators of natural killer (NK) of spleen cells in C3H/He mice.