Comparative study of antitumor activity and immunomodulatory effect of tetrahydro-2-furanyl and tetrahydro-2-pyranyl (1 leads to 3)-beta-D-glucans.

The effects of tetrahydro-2-furanyl- and tetrahydro-2-pyranyl-ethers of (1 leads to 3)-beta-D-glucans from Alcaligenes faecalis var. myxogenes (IFO 13140) on the activities of macrophages and natural killer (NK) cells in either ICR or BALB/c mice were studied. The derivatives with strong antitumor activity against Sarcoma 180 in ICR mice induced higher macrophage tumoricidal activity (greater than 40%) than those with low antitumor activity (less than 20%). All derivatives with high or low antitumor activity augmented NK cell activity. On the other hand, the derivatives which show the high antitumor activity against Meth-A in BALB/c mice enhanced macrophage tumoricidal activity, while those with low or no antitumor activity did not. NK cell activity was activated by the derivatives with or without the antitumor activity. Furthermore, certain derivative which has high antitumor activity against Sarcoma 180 in ICR mice did not increase serum component (LB) in ICR mice. These results indicate that the antitumor activity of the derivatives correlates only with the capacity to cause macrophage activation in vivo.