EFFECT OF BOLESATINE, A GLYCOPROTEIN FROM BOLETUS-SATANAS, ON RAT THYMUS IN-VIVO

Bolesatine is a glycoprotein purified to homogeneity from Boletus sata nas Lenz, a toxic mushroom which causes serious gastroenteritis. This lectin possesses a mitogenic activity on human lymphocytes at very low concentrations, whereas higher concentrations inhibit protein synthes is in vitro in several systems. The mitogenic activity on peripheral b lood T lymphocytes in vitro has been shown to be at least 200-fold hig her than the activity of the well studied phytohemagglutinin (PHA). In order to verify this property in vivo, the effect of bolesatine has b een studied in thymus of rats given orally bolesatine. Two groups of b olesatine-treated animals were used in addition to the control group. One group was given every 48 h, 28 mu g of bolesatine/kg body weight s even times and 150 mu g/kg body weight 48 h before the sacrifice. The other group was given 55 pg of bolesatine/kg body weight according to the same protocol and 150 mu g/kg body weight 48 h before the sacrific e. In these conditions, the ratio thymus weight/body weight is increas ed by 10% and 28%, respectively, in groups 1 and 2. Similarly, the DNA synthesis is increased by more than 50%, indicating that (i) bolesati ne probably possesses a mitogenic effect on thymocytes in vivo (ii) th at the increase of the ratio thymus weight/body weight is not due to s welling by water retention, but rather to a multiplication of thymocyt es. These results are confirmed in a second run of experiments in whic h bolesatine given orally to rats in lower doses of 3-12 mu g/kg induc es an increase of both thymus weight by 47% to 54% and an increase of total proteins by 52% to 56%, respectively, whereas the ratio total pr otein/g of thymus does not change. Thus bolesatine, known to be mitoge nic to human lymphocytes in vitro is also mitogenic to rat thymocytes in vivo.