In vivo antitumor effect of proteoglycan fraction from Agaricus brasiliensis does not depend on the production of antitumor antibodies / O efeito antitumoral in vivo da fração proteoglicana de Agaricus brasiliensis não depende da produção de anticorpos antitumorais

Abstract

Polysaccharides isolated from the edible mushroom Agaricus brasiliensis were previously shown to have antitumor, antiproliferative, and immunomodulatory activity. Here, we evaluated the in vivo effect of the acid-treated fraction from A. brasiliensis (ATF) on the subcutaneous growth of Ehrlich tumor cells (EHR) and on the production of tumor-specific antibodies. Mice (n=10) were inoculated with 2 × 106 EHR and injected subcutaneously in the tumor inoculum region with 0.1 mL ATF or saline. Control (tumor-free) group received ATF or saline. Treatments were carried out for 7, 14, or 30 days, with three consecutive doses and an interval of 4 days between the first and last doses, being repeated until the end of each experimental period. Histopathological analysis shows the infiltration of mononuclear and polymorphonuclear cells into the tumor site of all tumor-bearing mice. Tumor stimulated the influx of polymorphonuclear cells in the early stages, especially at 7 days, while the influx of mononuclear cells was higher in the final stages, at 14 and 30 days in all animals, independently of the treatment with ATF. Treatment of animals for 30 days reduced the tumor weight in 30% but we did not find a correlation with the antitumor antibody production since both treated and untreated mice were able to produce them.