Effects of anti-TGF-β type II receptor antibody on experimental glomerulonephritis

Abstract

Background. Renal fibrosis, characterized by the accumulation of extracellular matrix (ECM), is a common histopathological feature of progressive renal disease of diverse etiology. Interaction between transforming growth factor-β (TGF-β) and TGF-β type II receptor (TGF-βIIR) may play an important role in the ongoing fibrotic process. TGF-βIIR and TGF-β have been reported to be up-regulated in human glomerulopathies. In order to block the TGF-β system, many studies have inhibited TGF-β itself, but not its receptors. Our study explored the effects of fully human monoclonal antibody against TGF-βIIR (hTGF-βIIRAb) on experimental proliferative glomerulonephritis. Methods. hTGF-βIIRAb was generated from Xenomice. The expression of TGF-βIIR was studied by immunohistochemistry in normal and anti-Thy-1 nephritis rats. hTGF-βIIRAb or control Ab was injected intraperitoneally at day 0 and day 4 of anti-Thy-1 nephritis, and rats were sacrificed at day 7. Effects of hTGF-βIIRAb were assessed by histological and immunopathological measurements. Results. The specificity of hTGF-βIIRAb was confirmed by ELISA and Western blot analysis. By immunostaining, TGFβIIR expression was up-regulated in the proliferative lesions of anti-Thy-1 nephritis at day 7. In the hTGF-βIIRAb-treated group, the extent of mesangial expansion was less than that in the control group. By immunohistology, α-smooth muscle actin, fibronectin-EDA, and type I collagen were significantly reduced in the hTGF-βIIRAb-treated group. Conclusions. Anti-TGF-βIIR antibody ameliorated ECM accumulation in anti-Thy-1 nephritis. Our data suggest that TGF-βIIR may be one of the therapeutic targets, and that fully human monoclonal antibody against TGF-βIIR may have a new therapeutic potential for renal fibrosis.