A transgenic mouse model of autoimmune glomerulonephritis and necrotizing arteritis associated with cryoglobulinemia.

Mice implanted with hybridoma secreting 6-19 IgG3 anti-IgG2a rheumatoid factor (RF) with cryoglobulin activity develop acute glomerulonephritis and cutaneous leukocytoclastic vasculitis. As the RF activity is implicated in the skin, but not glomerular lesions, it is still unclear whether the renal pathogenicity is determined by 6-19 H chains alone or their combination with L chains. To address this question, we have generated transgenic mice expressing only the H chain gene or both H and L chain genes of the 6-19 IgG3 anti-IgG2a RF and determined the development of glomerular and vascular lesions.

Level of galactosylation determines cryoglobulin activity of murine IgG3 monoclonal rheumatoid factor.

Autoantibodies of the cryoprecipitating IgG3 isotype have been shown to play a significant role in the development of murine lupus-like autoimmune syndrome. At present, the structural basis of IgG3 cryoprecipitation and its role in autoantibody pathogenicity remain to be defined. Using molecular variants of an IgG3 monoclonal rheumatoid factor, 6-19, derived from an autoimmune MRL-Fas(lpr) mouse, we have investigated the implication of charged residues in the heavy-chain variable (VH) region, potential CH3-linked oligosaccharides, and galactosylation of CH2-linked oligosaccharides in its cryoglobulin activity.