Tumor-specific cytocidal and immunopotentiating effects of relatively low molecular weight products derived from the basidiomycete, Agaricus blazei Murill

Currently, some natural herbal extracts are believed to have a marked tumor icidal effect and low toxicity for normal tissues. We investigated the effe ct of relatively low molecular weight products extracted from the basidiomy cete, Agaricus blazei Murill, on MethA tumor cell growth with the aim of pr oducing synthetic derivatives based on these products. Inoculation of the l ow molecule fraction (LM) into the primary tumor of a two-tumor model resul ted in the marked inhibition of the tumor, nor only in the right flank, but also in the non-injected left flank. Chromatographic purification and phys iochemical characterization showed the main tumoricidal activity to be loca ted in a low molecule fraction-3 (LM-3), containing alpha-1,4-glucan-beta-1 ,6-glucan complex with an average molecular weight of 20 kDa. All LM fracti ons and crude ATF showed in vitro selective cytotoxicity for MethA tumor ce lls, having no effect on normal cells. Serum levels of immunosuppressive ac idic protein (IAP) in mice receiving LM fractions, particularly LM-3, signi ficantly increased, indicating the possible activation of granulocytes. We speculate that the inhibition of the distant tumor might be due to the incr eased migration of granulocytes, enhanced by the effect of extract injectio ns at the primary tumor site.