[Immunomodulating and antitumor activity of polysaccharides of plant origin].

The effect of the polysaccharides tagetan, palustran, and zymosan injections to BALB/c mice on the formation of cytotoxic T-lymphocytes in allogenic mixed culture has been studied. Lymphocytes from a 5-day-old mixed culture were characterized by the greatest cytotoxic activity, with spleenocytes serving as reacting cells in mice injected 12-50 mg/kg of tagetan, 20 mg/kg of zymosan and 10-100 mg/kg of palustran, 7, 3 and 5 days, respectively, before the beginning of allogeneic stimulation in vitro. To determine correlation between immunostimulating and antitumor activity 25 mg/kg of tagetan every 14 days, 20 mg/kg of zymosan every 6 days, and 10 mg/kg of palustran every 6 days, were injected to BALB/c and BALB/c nu/nu mice prior to and following subcutaneous implantation of Crocker sarcoma cells. By the end of the first month of immunotherapy the tumour size in mice on tagetan or zymosan was 2-2,5 times smaller than in control animals. Tumour growth inhibition with palustran was about 30%. Polysaccharide administration to BALB/c nu/nu mice was not accompanied by tumour growth inhibition. The data obtained suggest that inhibition of Crocker sarcoma growth in mice injected the above polysaccharides is mediated by stimulation of antitumour T-cell activity.