Abstract
SAITO, H., KITAME, F., UEMURA, Y. and ISHIDA, N. The Regulating Effect of Cholesterol Derivatives Isolated from Human Sera on Lymphocyte Response to Phytohemagglutinin. Tohoku J. exp. Med., 1983, 140 (3), 245-258-Cholesterol derivatives, including 7α-hydroxycholesterol (7α-HC), 7β-hydroxy-cholesterol (7β-HC), and 7-ketocholesterol (7-KC), were isolated from the Cohn fraction IV-I of normal human sera and were shown to be the moieties responsible for the suppression of lymphocyte proliferation. When 5-10μg/ml of 7α-HC, 7β-HC or 7-KC were added in vitro to lymphocyte cultures, incorporation of 3H-thymidine (3H-TdR) into the lymphocyte DNA was suppressed by about 50% when compared with the control. When 10-50mg/kg/day of 7α-HC, 7β-HC and 7KC were administered in vivo to skin grafts on rats, the prolongation of skin grafts was observed. The concentration of 7-KC in cancer patient sera was 2 to 3 times the amount in normal pooled human sera.
