Lectinocytochemical detection of apoptotic murine leukemia L1210 cells.

Abstract

Various cytomorphologic and biochemical markers of apoptosis are found in different compartments (plasma membrane, cytoplasm, nucleus, and mitochondria) of target cells. Although the plasma membrane is an easily accessible cellular compartment, relatively little is known about its changes during apoptosis. We investigated whether specific changes in the expression of plasma membrane glycoproteins take place during apoptosis and whether these changes could be used for a quantitative estimation of apoptosis. Lectin cytochemical study of normal and apoptotic murine leukemia cells of the L1210 line was done. Horseradish peroxidase-labeled Laburnum anagyroides bark agglutinin, Phaseolus vulgaris agglutinin, Pisum sativum lectin (PSL), Ricinus communis agglutinin (RCA-120; 120 kDa), Solanum tuberosum agglutinin, Triticum vulgaris lectin (wheat germ agglutinin), Viscum album agglutinin, Canavalia ensiformis lectin (concanavalin A), and Helix pomatia lectin were used to compare specific glycoprotein expressions in normal and apoptotic murine leukemia cells of the L1210 line sensitive (L1210) and resistant (L1210R) to apoptosis induction by cisplatin. The data demonstrated significantly increased binding of alpha-D-mannose-specific PSL lectin (P<0.01) and beta-D-galactose-specific RCA-120 lectin (P<0.001) by the apoptotic cells of the L1210 and L1210R lines in comparison with the intact cells. That binding was shown to be specific because it was blocked by the corresponding inhibitory sugars. Lectins specific to alpha-D-mannose (PSL) and beta-D-galactose (RCA-120) can be used to distinguish between native and apoptotic murine leukemia L1210 cells and to quantitatively estimate apoptosis in a population of these cells.