Characterization of reactivity of monoclonal autoantibodies with renal antigens in experimental lupus nephritis.

Mice with chronic graft-versus-host disease (GvHD), induced by injection of DBA/2 lymphocytes into (C57BL10*DBA/2)F1 hybrids, develop a lupus-like syndrome with immune complex glomerulonephritis. Circulating autoantibodies are reactive with various self-antigens, including DNA, renal tubular epithelium (RTE), and laminin-1. To elucidate the reactivity of autoantibodies with renal antigens in experimental lupus nephritis further, the reactivity of the autoantibodies was studied in more detail by generating hybridomas from GvHD spleen cells. Hybridomas were selected for reactivity with RTE and laminin-1 coated on nitrocellulose sheets. Four stable clones were obtained (GV1-GV4). Monoclonal antibody (mAb) GV1 showed no reactivity on kidney sections, while GV2 stained the brush border of proximal tubular epithelial cells. Both GV1 and GV2 reacted only with RTE in ELISA. GV3 showed a nuclear staining pattern, while GV4 stained matrix structures on F1 kidney sections. GV3 and GV4 both reacted with RTE, laminin-1, ssDNA, and dsDNA in ELISA. Growth of hybridomas in mice, but not passive transfer of the mAbs, led to glomerular Ig binding for mAbs GV3 and GV4 without development of proteinuria. Our results show that in addition to anti-nuclear autoantibodies cross-reactive with renal antigens, autoantibodies reactive with renal antigens and not with DNA are generated during chronic GvHD. Based on these results, combined with those of earlier experiments, we conclude that a combination of autoantibodies against multiple epitopes is necessary for the induction of glomerular damage in this model for lupus nephritis.