title: Non-Fc receptor-binding humanized anti-CD3 antibodies induce apoptosis of activated human T cells.
abstract: Human trials in organ allografts have demonstrated that murine anti-CD3 mAbs are immunosuppressive. By mimicking Ag, anti-CD3 can produce T cell activation, anergy, or death. Activation of resting T cells in vivo results in dose-limiting cytokine release and is caused by Ab-mediated cross-linking of T cells and Fcgamma receptor (FcR)-bearing cells. With the goal of minimizing cytokine-induced toxicity, anti-CD3 have been engineered to lower Fc binding avidity. Preclinical murine studies have indicated that non-FcR-binding anti-CD3 can induce apoptosis of Ag-activated T cells. Since induction of T cell apoptosis may be an important mechanism of immunosuppression by anti-CD3, we tested whether Fc mutations affect the ability of anti-human CD3 to induce apoptosis of activated T cells. We compared wild-type murine anti-CD3, M291, and OKT3 and their humanized, FcR- and non-FcR-binding structural variants in quantitative assays of T cell apoptosis. Non-FcR-binding variants produced more sustainable phosphorylation of extracellular signal-regulated kinase-2, greater release of IFN-gamma, and more effectively caused activation-dependent T cell apoptosis. Non-FcR-binding variants dissociated more quickly from the T cell surface and caused less internalization of the TCR, which then remained available in greater abundance on the cell surface for signaling. Cross-linking of non-FcR-binding variants by antiglobulin enhanced TCR internalization and minimized induction of T cell apoptosis. We conclude that non-FcR-binding, humanized anti-CD3 have improved ability to induce apoptosis of activated T cells, presumably by allowing durable expression of the TCR and sustained signaling.
authors.affiliation: Division of Clinical Research, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.
authors.forename: P A
authors.initials: PA
authors.lastname: Carpenter
authors.forename: S
authors.initials: S
authors.lastname: Pavlovic
authors.forename: J Y
authors.initials: JY
authors.lastname: Tso
authors.forename: O W
authors.initials: OW
authors.lastname: Press
authors.forename: T
authors.initials: T
authors.lastname: Gooley
authors.forename: X Z
authors.initials: XZ
authors.lastname: Yu
authors.forename: C
authors.initials: C
authors.lastname: Anasetti
mesh_terms: D000328:Adult; D000818:Animals; D000911:Antibodies, Monoclonal / Q000378:metabolism / Q000494:pharmacology*; D017209:Apoptosis / Q000276:immunology*; D001666:Binding Sites, Antibody; D017252:CD3 Complex / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D002453:Cell Cycle / Q000276:immunology; D002478:Cells, Cultured; D015536:Down-Regulation / Q000276:immunology; D006801:Humans; D007166:Immunosuppressive Agents / Q000378:metabolism / Q000494:pharmacology; D008213:Lymphocyte Activation / Q000276:immunology*; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D016853:Muromonab-CD3 / Q000378:metabolism / Q000494:pharmacology; D010766:Phosphorylation; D011947:Receptors, Antigen, B-Cell / Q000378:metabolism; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism; D011961:Receptors, Fc / Q000378:metabolism*; D012995:Solubility; D016176:T-Lymphocyte Subsets / Q000166:cytology* / Q000276:immunology* / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D017252:CD3 Complex; D007166:Immunosuppressive Agents; D016853:Muromonab-CD3; D011947:Receptors, Antigen, B-Cell; D011948:Receptors, Antigen, T-Cell; D011961:Receptors, Fc; D019950:Mitogen-Activated Protein Kinase 1