Upregulation of tenascin and TGF beta production in a type II alveolar epithelial cell line by antibody against a pulmonary auto-antigen

Type II alveolar epithelial cells express a 70-90 kDa antigen to which circ ulating auto-antibodies have been previously identified in patients with cr yptogenic fibrosing alveolitis (CFA). In vitro experiments have been conduc ted with a rabbit polyclonal antibody raised to this auto-antigen, and the type II epithelial cell line A549. This study examined possible effects tha t interaction of this antibody with type II epithelial cells might have on the production of cytokines and extracellular matrix components that may be important in the pathogenesis of CFA. There was a significant increase in TGF beta and tenascin, but not IL4, production by the A549 cells after cult ure with the immune serum. Further experiments showed that after 72 hours i n culture, the antibody decreased A549 cell number in a complement-dependen t process, which appeared to be cytostatic rather than cytolytic. These res ults indicate in vitro biological activity for this antibody and suggest a possible in vivo role for auto-antibody to type II epithelial cells in the pathogenesis of CFA. Copyright (C) 2001 John Wiley & Sons, Ltd.