LYSOSOMAL GLYCOSIDASES IN DIFFERENT POPULATIONS OF HUMAN THYMOCYTES

Lysosomal glycosidase activities were studied in human thymocyte fract ions obtained by two methods: (A) fractionation in Percoll density gra dient and (B) separation from the cells forming rosettes with sheep er ythrocytes (E-RFC). (A) affords fraction L, enriched with immature and endogenously activated thymocytes, and fraction H containing mature t hymocytes. By use of (B), fraction E-RFC enriched with non-activated i mmature thymocytes was obtained. Comparative study of E-RFC and H reve aled diverse alterations in activities of glycosidases during thymocyt e maturation, specifically decreases in alpha-L-fucosidase and alpha-D -mannosidase and an increase in beta-D-galactosidase. Comparing E-RFC and L demonstrates increases in activities of studied glycosidases fol lowing endogenous activation of thymocytes.