Fig. 3: ABO blood group glycans at the cervicovaginal interface and interaction with common vaginal microbiota.

a Representative MALDI-TOF mass spectrum of O-glycans released from CVF of an A blood group and B blood group donors. Assignments are based on composition, tandem MS and knowledge of biosynthetic pathways. All molecular ions are [M+Na]⁺. b Semi-quantitative analyses of whole spectrum show higher percentages of A and B blood group epitopes expressed on O-glycans than on N-glycans. n = 64. c The highest abundance of the A blood group antigen on glycans isolated from CVF is detected in association with CST-I and term delivery, whereas the presence of the B antigen, which is lower in abundance, is seen across all CSTs, and is predominantly seen in women who have a preterm delivery. Mass range 3000-4000 for N-glycan analysis, whole spectrum for O-glycan analysis. n = 46. d A schema of glycan microarrays constructed to detect glycan binding with fluorescently labelled in-house cultured bacterial isolates of species and strains. e Heatmap showing the relative binding intensities to blood group glycan probes at pH4 and pH7 of fluorescently labelled bacteria. Differential binding of commensals and pathobionts is seen depending on ABH backbone and pH. The average rank of mean fluorescence intensities of quadruplicate spots from three binding assays was calculated and the resulting values coloured as follows: Dark blue (0-10%); Light blue (10-25%); Yellow (25-50%); Orange (50-70%); Red (70-100%). 100%, the maximum binding score observed across pH4 and pH7 for a given strain.