The lectin DBA recognizes glycan epitopes on the surface of murine embryonic stem cells: a new tool for characterizing pluripotent cells and early differentiation

¹ Center for Complex Carbohydrate Research and Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia
² Department of Molecular Biosciences, University of Adelaide, Australia

^* To whom correspondence should be addressed. E-mail: sdalton{at}uga.edu.

	Abstract

Cell surface markers are key tools that are frequently used to characterize and separate mixed cell populations. Existing cell surface markers used to define murine embryonic stem cells (mESCs) such as stage specific embryonic antigen 1 (SSEA1), Forssman antigen (FA), alkaline phosphatase (AP) and CD9 are limiting however because they do not unambiguously define the pluripotent state and are not reliable indicators of differentiation commitment. To identify glycan cell surface markers that would circumvent this problem we used a panel of eighteen lectins to identify epitopes specifically elevated on the surface of mESCs which, during differentiation, decrease with kinetics that precede currently used markers such as CD9, SSEA1, FA and AP. The anticipated outcome of this analysis was to identify glycans that have utility as a reliable mESC marker and as a high resolution readout for early differentiation commitment. Here we show that the lectin Dolichos biflorus agglutinin (DBA), recognizes -N-acetylgalactosamine (GalNAc) cell surface epitopes on mESCs (CD9^high SSEA1^high AP^high DBA^high). These glycan epitopes decline markedly in cells undergoing the first definable step of differentiation, the transition from mESCs to primitive ectoderm (CD9^high SSEA1^high AP^high DBA^low). Loss of GalNAc epitopes is therefore the earliest cell surface change that can be assigned to differentiating cells and, the only cell surface marker known to be tightly associated with the pluripotent state. The lectin DBA is therefore a useful tool to characterize mESC cultures by non-destructive approaches, an indicator of differentiation commitment and a predictor of developmental potency.