No abstract

The effect of dianhydrodulcithol (DAD) administered in a dose of 5 mg/kg on the number of plaque-forming cells (PFC) in spleens and on the titre of hemolytic antibodies in the sera of rats immunised with sheep red blood cells (SRBC) have been examined. The compound elicited a short-lasting suppressive effect when applied after immunisation; the number of PFC decreased two days after treatment while 5 days after drug administration increased as compared to the untreated animals. Treatment prior to immunisation proved to be ineffective. The titre of circulating antibodies showed changes similar although of lesser extent. Five days following treatment marked infiltration of plasmacytes was present in the axillary lymph nodes. Rats bearing transplantable Guerin tumor showed similar changes in immune response as the tumor free animals following DAD treatment.

The number of direct plaque-forming cells and the titer of circulating hemolytic antibodies were studied at different times after transplantation of Guérin tumor in rats. A stimulating effect was observed 5 days after tumor transplantation. In the terminal stageof tumor development the immune responsiveness was reduced. When irradiated, nongrowing tumor tissue was transplanted, an increased immune response could be observed shortly after transplantation while a loss in immune response did not develop up to the 21st day after transplantation.