Raising primary antibodies against the carbohydrates themselves is problematic with so many carbohydrate structures being involved in immune signalling pathways when antibody technologies were being initially developed, since glycosylation influences the function of all immune cells. Glycans play a crucial role in intercellular contacts and leukocytes migration. These interactions are important in activation and proliferation of leukocytes and during immune response.(4)
SigLecs are sialic acid binding ImmunoGlobulin-type Lectins – a whole family of proteins expressed by cells of the immune system - that are sensitive to variations in the presentation of sialic acid and it is suggested that different immune responses can be generated based on the Sialic acid linkage detected.
Lectins can have a number of sugar recognition sites, with the binding affinity increasing with the number of correct matches between the lectin and the carbohydrate, which also relies on the spatial presentation of the sugars. The strength of the binding of a lectin to a sugar can therefore also help to distinguish between different isotypes of carbohydrate that would appear the same on a mass spectrometer.
Of themselves, lectins are a study area of interest. Some of the well-characterized roles of lectins are in cell-cell communication, cancer metastasis, embryogenesis, host-pathogen interactions, and tissue development (5).