Size-dependent binding of IgA to HepG2, U937, and human mesangial cells

IgA nephropathy (IgAN) is characterized by increased circulating IgA and mesangial IgA deposition. The mechanism of mesangial IgA deposition remains poorly understood in IgAN. In this report, we studied the binding characteristics of serum IgA from patients with IgAN and healthy controls to different cell types, including a liver-cell line (HepG2), a monocytic cell line (U937), and human mesangial cells (HMCs). Jacalin-bound proteins (JBPs) were purified from serum IgA by means of jacalin affinity chromatography. Total IgA concentrations were significantly higher in patients with IgAN than in controls (P