Asparagine-linked sugar chains of plasma membrane glycoproteins from healthy and common variable immunodeficiency B lymphoblastoid cell lines

Asparagine-linked sugar chains of plasma membrane glycoproteins, which are formed by glycosylation during B cell maturation, were examined with B lymphoblastoid cell lines (LCLs) transformed by Epstein-Barr virus derived from healthy controls and patients with common variable immunodeficiency (CVI). Both two patients with CVI showed hypogammaglobulinemia and impaired B cell functions. LCLs from healthy controls and the patients showed CD19+ and HLA/DR+ in the cell surface and secreted IgM. In both healthy controls and the patients, the main oligosaccharide in asparagine-linked sugar chains of the membrane glycoproteins of LCLs was biantennary sugar chain with bisected GlcNAc (Gal₂-GlcNAc₂-Man₃-GlcNAc-GlcNAc-Fuc-GlcNAc_OT). Biantennary sugar chain with an-fucosyl residue linked at the proximal GIcNAc was seen but biantennary sugar chain without an-fucosyl residue at the proximal GlcNAc was little detected in each LCL. There was no difference in quality and quantity of asparagine-linked sugar chains between healthy controls and the patients. These results suggest that glycosylation during B cell maturation may not be impaired in patients with CVI.