T-lymphocytic leukemia expresses complex, branched O-linked oligosaccharides on a major sialoglycoprotein, leukosialin.
Leukocytes express a major sialoglycoprotein, leukosialin, of which the apparent molecular weight (mol wt) can be variable according to the differences in O-glycans attached to this molecule. In the present study, we analyzed the structures of O-glycans attached to leukosialin present in various T-lymphocytic leukemia cells. T-lymphoid cells from patients with acute T-lymphocytic leukemia express a large amount of the branched hexasaccharides, NeuNAc alpha 2----3Gal beta 1----3(NeuNAc alpha 2----3Gal beta 1----4GlcNAc beta 1----6)GalNAc, which are also expressed in activated normal T lymphocytes, but that are almost absent in resting normal T lymphocytes. T-lymphoid cells from patients with chronic T-lymphocytic leukemia, on the other hand, mainly express the tetrasaccharides NeuNAc alpha 2----3Gal beta 1----3(NeuNAc alpha 2----6)GalNAc on leukosialin, but they also express a small significant amount of the hexasaccharides. The same hexasaccharides can be detected in thymocytes. The increased amount of the hexasaccharides in acute leukemia is associated with increased activity of beta 1----6 GlcNAc-transferase, a key enzyme in forming the hexasaccharides. Immunoblot analysis of cell lysates showed that monoclonal antibody (MoAb) T-305 reacts preferentially with leukosialin of high mol wt containing the hexasaccharides. These findings indicate that T-lymphocytic leukemia cells reexpress the oligosaccharides present in immature cells.
Saitoh
O
O
La Jolla Cancer Research Foundation, Cancer Research Center, CA 92037.
Piller
F
F
Fox
R I
RI
Fukuda
M
M
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D002850:Chromatography, Gel; D006801:Humans; D015458:Leukemia, T-Cell / Q000378:metabolism*; D051917:Leukosialin; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009844:Oligosaccharides / Q000096:biosynthesis* / Q000302:isolation & purification; D012795:Sialoglycoproteins / Q000032:analysis / Q000096:biosynthesis* / Q000302:isolation & purification; D014166:Transferases / Q000378:metabolism
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D051917:Leukosialin; D009844:Oligosaccharides; C465014:SPN protein, human; D012795:Sialoglycoproteins; D014166:Transferases