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 controlling this reaction,biocompatibility could be improved. We previously demonstrated that impregnation of a biodegradable biomaterial with antibodies against interferon-gamma (IFN-gamma) inhibits the foreign body reaction. In this study we investigate whether systemic administration of the antibody can induce similar reactions. Several parameters are compared between control and anti-IFN-gamma-treated rats: cellular ingrowth; degradation of the biomaterial; ingrowth of macrophage (MO) subsets, T cells, B cells, NK cells, and granulocytes; and expression of the major histocompatibility complex class II (MHC class II) molecule on antigen presenting cells. Treatment with anti-IFN-gamma results in increased cellular ingrowth and biomaterial degradation and a decreased expression of MHC class II. Overall, systemic treatment with anti-IFN-gamma is insufficient to modulate the foreign body reaction. This suggests an alternative mechanism for MO activation besides IFN-gamma. The role of T cells and MO subsets in the foreign body reaction is discussed. (C) 2000 John Wiley & Sons, Inc.