INDUCTION OF TOLERANCE BY T-CELL VACCINATION IS POSSIBLE BEYOND THE AREA OF AUTOIMMUNITY - DOWN-REGULATION OF IMMUNITY DIRECTED TO FOREIGN PROTEIN ANTIGENS

T-cell vaccination using antigen-specific lines or clones has been sho wn to be effective in downregulating immunity in various experimental autoimmune models. Anti-idiotypic networks developing during different iation of the immune system are considered to be a safeguard against a utoimmunity and these pre-existing networks are supposed to be a prere quisite for successful vaccination. However, the interesting question of feasibility of T-cell vaccination beyond the area of autoimmunity r emains to be answered. The present study is the first one providing ev idence of successful T-cell vaccination in mice immunized against fore ign protein antigens (in this system supposedly no pre-existing networ k exists). Intraperitoneal (i.p.) administration of hen egg lysozyme ( HEL)- and chicken egg albumin (OVA)-specific lymph node cells (LNC) we re shown to effectively down-regulate immunity (as measured in a delay ed type of hypersensitivity) to HEL and OVA, respectively. In contrast , vaccination was unsuccessful with methylated bovine serum albumin (m BSA)specific LNC in mBSA immunity. Suppression induced by HEL- and OVA -specific LNC was antigen specific. Unlike the greater part of other s tudies, in which antigen-specific lines or clones were used; we used d raining LNC of immunized mice, which after activation were fixed with glutardialdehyde and injected i.p. 10 days before immunization. Finall y, effects of T-cell vaccination were studied in a chronic HEL-induced arthritis. Joint swelling, cell influx and cartilage matrix depletion were significantly less in mice treated with antigen-specific cells. We conclude that successful vaccination is feasible in mice rendered i mmune to foreign protein antigens using a pool of LNC as source of vac cine, suggesting no necessity of a strong pre-existing network.