Chlorella vulgaris culture supernatant (CVS) reduces psychological stress-induced apoptosis in thymocytes of mice

A glycoprotein prepared from Chlorella vulgaris culture supernatant (CVS) i s a biological response modifier (BRM) which exhibits protective activities against tumor metastasis and 5-fluorouracil-induced immunosuppression. We here show that oral administration of CVS prevented significantly the apopt osis of thymocytes in mice undergoing psychological stress in a communicati on box. Mice were exposed to the emotional stress for 14 days by witnessing other mice being exposed to foot-shock. The numbers in thymocytes, especia lly CD4(+)CD8(+) population, were decreased significantly and apoptotic cel ls, as assessed by Annexin V expression, were reciprocally increased after the exposure to the psychological stress. C. vulgaris culture supernatant ( CVS) administration significantly suppressed the increase in serum corticos terone level in the psychologically stressed mice. These results suggest th at CVS prevents psychological stress and maintain homeostasis in the face o f external environmental changes. (C) 2000 International Society for Immuno pharmacology. Published by Elsevier Science Ltd. All rights reserved.