A panel of biotin-label lectins is used to interrogate bacterial extract and purified lipopolysaccharides arrayed on a 16 pad ONCYTE Supernova microarray slide.
Bacterial surfaces are decorated with short chain lipopolysaccharides (LOSs). These molecules mediate bacterial mobility and cell adhesion. They are also involved in the host immune system evasion and modulation. In fact, one of the mechanisms bacteria employ to avoid detection from the host’s immune system is to display, on their outer membrane, LOSs that mimic carbohydrate moieties normally present on eukaryotic cells surface  . A relevant example is Haemophilus influenzae, whose LOS may display the Galα (1,4)Galβ epitope characteristic of P1PK blood group antigens. Expression of this disaccharide prevents recognition by naturally acquired antibodies and complement- and neutrophil-mediated killing.
Plant lectins have been known for their ability to recognize and bind to sugar epitopes. This property of lectins is routinely exploited in agglutination assays for bacterial typing.
In this study, Grace Bio-Labs microarray substrates are employed for the quantitative analysis of lectin-bacteria interactions of Haemophilus influenza strains. A panel of biotin-labeled lectins is used to interrogate bacterial extract and purified lipopolysaccharides arrayed on a 16 pad ONCYTE® Supernova microarray slide.
Strong binding signals were observed for the lectins to microarray-printed LOS. The binding was demonstrated to be carbohydrate-mediated as it was inhibited by lactose.
This study demonstrates lipopolysaccharides microarrays can be an effective tool for the identification of lectin-ligand candidates and have the potential to be applied in diagnostics and seroepidemiology.
- Kumar, H., Kawai, T. & Akira, S. Pathogen recognition by the innate immune system. International Reviews of Immunology 30, 16–34 (2011).
- Raetz CR, Whitfield C. Lipopolysaccharide endotoxins. Annu Rev Biochem. 2002;71:635-700. (2001).
- Thirumalapura N.R., Morton R.J., Ramachandran A., Malayer N.R., Lipopolysaccharide microarrays for the detection of antibodies, Journal of Immunological Methods. Volume 298, Issues 1–2, (2005).
For more information: