Systemic anti-IFN-gamma treatment and role of macrophage subsets in the foreign body reaction to dermal sheep collagen in rats

The application of a biomaterial induces a foreign body reaction. By contro lling this reaction,biocompatibility could be improved. We previously demon strated that impregnation of a biodegradable biomaterial with antibodies ag ainst interferon-gamma (IFN-gamma) inhibits the foreign body reaction. In t his study we investigate whether systemic administration of the antibody ca n induce similar reactions. Several parameters are compared between control and anti-IFN-gamma-treated rats: cellular ingrowth; degradation of the bio material; ingrowth of macrophage (MO) subsets, T cells, B cells, NK cells, and granulocytes; and expression of the major histocompatibility complex cl ass II (MHC class II) molecule on antigen presenting cells. Treatment with anti-IFN-gamma results in increased cellular ingrowth and biomaterial degra dation and a decreased expression of MHC class II. Overall, systemic treatm ent with anti-IFN-gamma is insufficient to modulate the foreign body reacti on. This suggests an alternative mechanism for MO activation besides IFN-ga mma. The role of T cells and MO subsets in the foreign body reaction is dis cussed. (C) 2000 John Wiley & Sons, Inc.