T-CELL IMMUNE-RESPONSES TO HAPTENS - STRUCTURAL MODELS FOR ALLERGIC AND AUTOIMMUNE REACTIONS

Protein-reactive chemicals, metal salts and drugs, commonly classified as immunological haptens, are major environmental noxes targeted at t he immune system of vertebrates. They may not only interfere with this defense system by toxicity alone, but more often by evoking hapten-sp ecific immune responses resulting in allergic and eventually autoimmun e responses. Here, we review recent developements in the analysis of t he structural basis of hapten recognition, particularly by T lymphocyt es, which represent central elements in cell-mediated, as well as in I gE-dependent, allergies. A break-through in this field was the finding that T cells detect haptens as structural entities, attached covalent ly or by complexation to self-peptides anchored in binding grooves of major histocompatibility antigens (MHC-proteins). Synthetic hapten-pep tide conjugates were shown to induce hapten-specific contact sensitivi ty in mice, opening new routes for studying hapten-induced immune diso rders.