Figure 1 - Glycan diversity in human upper respiratory tissues.

(a) Costaining of tracheal tissue sections with ConA (red)/Jacalin (green) and SNA-I (red)/Jacalin (green). The localized regions of Jacalin binding correspond to goblet cells expressing O-linked glycans and the regions of conA binding correspond to ciliated cells expressing N-linked glycans (white arrow) on the apical side of the tracheal epithelium. The extensive binding of SNA-I to both goblet cells (costain with Jacalin in yellow) and ciliated cells indicates predominant expression of O-linked and N-linked 2-6 on the apical side. (b) MALDI-MS glycan profile of human bronchial epithelial (HBE) cells using graphical representation (without explicit linkage assignment) of possible sialylated glycan structures that satisfy the mass peaks (within 3.5 Daltons). HBEs predominantly express 2-6 (in comparison with 2-3) sialylated glycans (Supplementary Fig. 1). (c) Desialylation using Sialidase A and subsequent 2-AB labeling of the N-linked glycans observed in b to deconvolute the branching pattern from the number of sialic acids. The peaks highlighted in cyan in b and c were further analyzed using TOF-TOF MS. (d) The MS-MS profile of a representative peak at m/z 2148 shows critical fragment ions at m/z 548 and 713 and their corresponding counter ions (shown in red) that support the long oligosaccharide branch (with multiple lactosamine repeats) over multiple short lactosamine branches. MS-MS profile of m/z 2660 also supports a long oligosaccharide branch (data not shown). Glycans are represented using the graphical nomenclature adopted by the Consortium for Functional Glycomics (CFG).