The carbohydrate (CHO) moieties attached to glycoproteins are proving to be important loci for detection and regulation of cellular activity. Changes to the CHO moieties are linked to the presence of pre-cancerous and cancerous changes in the cells and tissues. In particular, changes in sialic acid bonds between 2,3 and 2,6 linkages may be important indicators of disease, but unfortunately an effective way of precisely measuring these linkages in biological samples does not yet exist. The various HA proteins (bird flu, swine flu, human flu) bind to 2,3- and 2,6-sialic acid bonds as a preliminary step for infection within the host. We hypothesized that HA proteins could be used to detect specific presentations of sialic acid moieties on glycoproteins captured from biological samples. In this study we used a simple method of multimerizing the HA protein to increase its binding avidity, and applied the HA proteins to the detection of sialic acids on biological glycoproteins. Using that specificity to detect changes in glycoprotein CHO structures, we discovered that the HA probes can differentiate between 2,3- and 2,6- sialic acid bond types in an efficient and reproducible manner. Studies also are underway to determine the relationship between sialic acid linkages and the presence of pancreatic cancer. This approach may provide robust and sensitive measurements of specific sialic acid presentations in biological samples.
Available at: http://works.bepress.com/david_nowack/2/