Improved methods for studying
glycans could spur significant advances in the understanding and application of glycobiology. The use of affinity
reagents such as
lectins and
glycan-binding
antibodies is a valuable
complement to methods involving mass spectrometry and chromatography. Many
lectins, however, are not useful as analytic tools due to low affinity in vitro. As an approach to increasing
lectin avidity to targeted
glycans, we tested the use of
lectin multimerization. Several biotinylated
lectins were linked together through
streptavidin interactions. The binding of certain
lectins for purified
glycoproteins and
glycoproteins captured directly out of
biological solutions was increased using multimerization, resulting in the detection of lower concentrations of
glycoprotein than possible using monomeric detection. The analysis of
glycoproteins in plasma samples showed that the level of binding enhancement through multimerization was not equivalent across patient samples.
Wheat germ agglutinin (WGA) reactive
glycans on
fibronectin and thrombospondin-5 were preferentially bound by multimers in
pancreatic cancer patient samples relative to control samples, suggesting a
cancer-associated change in
glycan density that could be detected only through
lectin multimerization. This strategy could lead to the more sensitive and informative detection of
glycans in
biological samples and a broader spectrum of
lectins that are useful as analytical
reagents.