Inhibition of tumor growth and leukocyte alterations in splenectomized mice treated with a PCj3 polysaccharide

The effect of a polysaccharide (PCj3), isolated from the ascomycete "Cyttaria johowii" was studied on the growth of the ascitic Sarcoma 180 (S180) inoculated subcutaneously in BALB/c mice which had been previously splenectomized. The leukocyte alterations in peripheral blood were analyzed simultaneously, and the percentage of cells with C3b receptors in the population of peritoneal cavity was evaluated through the E (IgM)C rosette technique. A significant inhibition of tumor growth was observed in the splenectomized mice treated with PCj3 with respect to the untreated splenectomized and to the control group, which had not been splenectomized. It was also found that the first group acquired relative resistance to the later inocula of the ascitic S180 via i.p. On the day 8 after the tumor inoculation a marked lymphocytosis increased up to 224% in PCj3 treated mice and only to 59% in untreated splenectomized mice. The increase in the controls, that had not been splenectomized was 18%. With regard to the number of neutrophils a significant difference was found between both splenectomized groups on the 8 day, corresponding the highest values to the group treated with PCj3. No differences were observed on the 25 day even though the neutrophilia was maintained. The percentage of cells with C3b receptors in population of peritoneal cavity was significantly lower in mice treated with PCj3, although an increase in the number of E (IgM)C attached per cell and ingestion of system were observed.