Journal: Scientific Reports
Article Title: Spatial mapping of influenza and coronavirus receptors in the respiratory and intestinal tract epithelium of beef cattle using advanced PixF image analysis
doi: 10.1038/s41598-025-28429-0
Figure Lengend Snippet: Sialic acid distribution in the beef cattle respiratory tract. ( A – JJ ) Confocal microscopy images of fluorescently labeled lectins Sambucus nigra (SNA, FITC, green) specific for sialic acid (SA) α2,6-Gal, Maackia amurensis II (MAL II, DyLight 650, red) specific for SA α2,3-Galβ (1–3) GlcNAc, and Maackia amurensis I (MAL I, FITC, green) specific for SA α2,3-Galβ (1–4) GlcNAc. Blue represents nuclear staining using DAPI; scale bar = 20 µM. Representative merged images showing SNA/MAL II binding ( A – E ) and MAL I/MAL II binding ( F – J ). Multifocal, apical membranous (white arrow) MAL II labeling was observed on trachea epithelium and extensively on basal cells (orange arrow) ( A ), while goblet cells (arrowhead) showing intense cytoplasmic SNA ( Ai ) and MAL II ( Aii ) labeling. Image analysis of tracheal epithelial lining (3D plot of insert in A ) showing greater MAL II labeling even in co-localized areas (arrow), and slightly higher SNA in goblet cell (arrowhead) ( Aiii ). Sub-mucosal areas showing both SNA and MAL II ( B ), with higher SNA in lamina propria connective tissue (asterisk) and higher MAL II in glands (dashed white outline). The 3D plot of insert in ( B ) demonstrated varying levels of expression of MAL II (arrow) and SNA (arrowhead) ( Biii ). Goblet cells and epithelial lining of the bronchus, bronchiole, and alveoli show intense MAL II labeling (arrow) ( C , D , E ) with SNA labeling in the lamina propria of the bronchus (white asterisk) ( C ) and the interstitial region of the alveolar wall (asterisk) ( E ). Quantitative image analysis confirmed that the lining of epithelial cells has higher membranous MAL II labeling (arrow) ( Ciii , Diii , Eiii ). MAL I demonstrated a labeling distribution analogous to that of MAL II, albeit with attenuated signal intensity ( F , H – J ), reflected in quantitative image analysis ( Fiii , Hiii – Jiii ). MAL I is more robust in the submucosal glands of the trachea (dashed white outline) ( G , Giii ). ( K – O ) Confocal images of the respiratory tract showing SA N-glycolylneuraminic acid (Neu5Gc, FITC, green) following immunofluorescence staining. Neu5Gc was detected on the apical membrane and cell borders of ciliated pseudostratified epithelia of the trachea ( K ), multifocally on the epithelial lining of the bronchus ( M ), bronchiole ( N ), and the alveoli ( O ). The sub-epithelial glands in the tracheal region also showed Neu5Gc ( L ).
Article Snippet: The sections were then incubated overnight (16 h) at 4 °C in a humidified chamber with optimized concentrations of 10 μg/ml fluorescein isothiocyanate (FITC) labeled SNA (Cat# FL-1301-2, Vector Laboratories) or 10 μg/ml FITC labeled MAL I (Cat# FL-1311-2, Vector Laboratories), and 5 μg/ml MAL II (Cat# B-1265-1, Vector Laboratories).
Techniques: Confocal Microscopy, Labeling, Staining, Binding Assay, Expressing, Immunofluorescence, Membrane