Chemoenzymatic Labeling Pathogens Containing Terminal N-Acetylneuraminic Acid-alpha(2-3)-Galactose Glycans

The N-acetylneuraminic acid-alpha(2-3)-galactose epitope is often located at the nonreducing terminal ends of glycans on the envelopes of many pathogens, and it is believed that this structure mimics a host's oligosaccharide so as to circumvent and/or counteract the host's immune responses. A chemoenzymatic method for the rapid and sensitive detection of N-acetylneuraminic acid-alpha(2-3)-galactose has been built, so we planned to examine whether the chemoenzymatic method could be applied on the detection of N-acetylneuraminic acid-alpha(2-3)-galactose on pathogens. Our results revealed that the chemoenzymatic method was rapid and sensitive for labeling live or dead Gram- positive Streptococcus agalactiae A909 and Gram-negative Campylobacter jejuni MK104 with N-acetylneuraminic acid-alpha(2-3)galactose. This study suggested that the chemoenzymatic method was a new strategy for labeling pathogens and had potential for the diagnosis of or therapeutics for pathogenic infection.