The Analysis of N-Linked Glycans in Human Serum

Proper glycosylation of immunoglobulin G (IgG) is essential for its normal function in the immune system and it also significantly affects efficacy of therapeutic antibodies. Previous studies clearly demonstrated that glycosylation of highly conserved glycan is attached to Asn-297 residue of IgG changes in different diseases (autoimmune, inflammatory, neoplastic), but it is not clear whether these changes are a consequence of a disease, or previously existing variability that might be a predisposition for the development of a disease. By applying recently developed high- throughput HPLC method we will analyze glycosylation of IgG isolated from plasma of 2000 – 3000 individuals. As a part of another project that we participate in, numerous biochemical, physiological, and genetical analyses have been performed in the same individuals, including complete genomics of 300.000 single nucleotide polymorphisms (SNPs). Genome- wide association studies of these polymorphisms and glycan levels will identify genes and polymorphisms that underlie variability in IgG glycosylation. Very little is known about genetic regulation of glycosylation, and this work that represents combination of two very recently developed powerful tools in two rather distant fields (glycobiology and genetics) is expected to provide significant insight into complex genetics of glycosylation in B lymphocytes. Insight into influence of common genetic polymorphisms on glycan structures will enable us to differentiate between glycosylation changes that occur as a consequence of altered disease physiology, and glycan variability that is genetically caused and might be a predisposition for the development of a disease.