A substance reacting with sheep red blood cells. Its relation to cortisone-resistant thymocytes

Abstract A substance reacting with sheep red blood cells, autologous red blood cells and rabbit IgG was previously isolated from thymus and spleen, but was not detected in bone marrow and liver. The isolation was performed by drastic treatment of rat thymus followed by affinity chromatography on IgG-cellulose adsorbents. Another method of isolation which includes incubation of thymocytes with IgG-cellulose adsorbent was adopted. According to i.r. spectroscopy data the affinity of both preparations to erythrocytes is due to the same substance. The yield of this substance, calculated to 1 mg of thymus tissue, increases in the rats treated by hydrocortisone. Since the decrease of the thymus weight after the treatment o rats by hydrocortisone does not lead to a decrease in the yield of this substance, the data tends to conclude that the above mentioned substance belongs to the cortisone-resistant subpopulation of thymocytes.