title: Novel method for in vitro depletion of T cells by monoclonal antibody-targeted photosensitization.
abstract: An immunotargeting method (called photo-immunotargeting) has been developed for selective in vitro cell destruction. The procedure combines the photosensitizing (toxic) effect of light-induced dye-molecules, e.g., hematoporphyrin (HP) and the selective binding ability of monoclonal antibodies (mAb) to cell surface molecules. The photosensitizer HP molecules were covalently attached to monoclonal antibodies (a-Thy-1) recognizing an antigen on the surface of T lymphocytes, and used for T cell destruction. To increase the selectivity of the conventional targeting methods, a physical activation step (local light irradiation) as a second degree of specificity was employed. The HP in conjugated form was sufficient to induce T cell (thymocytes, EL-4 cell line) death after irradiation at 400 nm, at tenfold lower concentration compared to the photosensitizing effect of unbound HP. The selective killing of T lymphocytes (bearing the Thy-1 antigen) in a mixed cell population was demonstrated after a treatment with the phototoxic conjugate and light irradiation. This method can be useful for selective destruction of one population (target cell) in an in vitro heterogeneous cell mixture, e.g., in bone marrow transplants for T cell depletion to avoid graft vs. host reaction.
authors.affiliation: Department of Immunology and Biotechnology, University Medical School of Pécs, Hungary. btimi@apacs.pote.hu
authors.forename: T
authors.initials: T
authors.lastname: Berki
authors.forename: P
authors.initials: P
authors.lastname: Németh
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D006415:Hematoporphyrins / Q000494:pharmacology*; D007518:Isoantibodies / Q000276:immunology*; D008212:Lymphocyte Depletion / Q000379:methods*; D051379:Mice; D008807:Mice, Inbred BALB C; D017319:Photosensitizing Agents / Q000494:pharmacology*; D051381:Rats; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology*; D014407:Tumor Cells, Cultured
chemical_list: D000911:Antibodies, Monoclonal; D006415:Hematoporphyrins; D007518:Isoantibodies; D017319:Photosensitizing Agents; C035678:anti-Thy antibody