De-sialylated and sialylated IgG anti-dsDNA antibodies respectively worsen and mitigate experimental mouse lupus proteinuria and possible mechanisms

•Highly sialylated IgG anti-dsDNA prevented and ameliorated proteinuria in lupus mice; this effect was mainly supported by elevated serum IL-10/IL-12 ratios, increased serum TGF-β1 level, and reduced serum TNF-α levels.•De-sialylated IgG anti-dsDNA aggravated proteinuria in lupus mice.•The α-2,6-SIA/serum IgG anti-dsDNA ratio inversely indicated the severity of the lupus-induced renal pathology.•One subclone of IgG anti-dsDNA (A52L1 IgG) mediated its action on the elevated SIA/anti-DNA ratio at least partly via elevated JAK2 expression.