engleski

Newly synthesized Man9-glycoprobe enables direct analysis of mannan binding lectin activity in human serum

Numerous biological processes are based on highly specific interactions between oligosaccharide structures of glycoconjugates and their receptors, lectins. However, precise biological roles of many lectins are still mostly unknown, partly because of the lack of adequate methods that could enable analysis of lectin activity. Aiming to improve tools for the analysis of lectins, we have recently developed a new class of complex neoglycoconjugates named Glycoprobes (Glycobiology 10:357, 2000). Glycoprobes consists of an oligosaccharide ligand, photoreactive crosslinker and a digoxin tag, and enable direct analysis of lectin activity in complex biological samples. The mannan binding lectin (MBL) plays a major role in innate immunity through its ability to activate complement upon binding to carbohydrate arrays on the surface of various microorganisms. It is a C-type lectin with a typical soluble collectin structure. To be able to analyze MBL activity in human serum we synthesized a specific glycoprobe containing Mannose9-N-Acetylgalactosamine2 (Man9) glycan as a ligand. Using Man9-glycoprobe we assayed MBL activity in 30 sera of patients with rheumatoid arthritis and 25 sera of matching healthy controls. It is important to note that this was the first example where activity, and not the simple presence of MBL protein was assayed. Very large biological variability of MBL activity was found to exist in both studied groups, while there appeared to be no significant difference between the groups. This result does not support the hypothesis that binding of MBL to degalactosylated oligosaccharides on IgG is an important element in the pathology of rheumatoid arthritis.

Man9 glycoprobe; activity of lectins; mannan binding lectin

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