title: Target-dependent T-cell activation by coligation with a PSMA x CD3 diabody induces lysis of prostate cancer cells.
abstract: Recently, we have described a bispecific PSMA x CD3 diabody with one binding site for the T-cell antigen receptor (TCR-CD3) and another for the Prostate Specific Membrane Antigen (PSMA). It effectively eliminates human prostate cancer cells by redirecting T-lymphocytes in vitro and in vivo. Here, we show that activation of the T-cells and killing of the tumor cells, only occurred when the T-cells were coincubated with PSMA-positive tumor cells and the PSMA x CD3 diabody. Both CD4+ and CD8+ human T-lymphocytes were activated. Surprisingly, they were equally potent in their cytotoxic activity, proliferation, and up-regulation of activation markers. Both, CD4+, and CD8+ T-cells mainly used the perforin-granzyme- based pathway and to a somewhat lesser extent the FasL pathway to lyse tumor cells. When Jurkat T-cells were stimulated with the diabody alone, the TCR-CD3 was not triggered. In contrast, when the diabody was clustered with a secondary antibody the TCR-CD3 was stimulated as detected by Ca(2+)-influx and Erk, IkappaB, and linker of activated T-cell phosphorylation. Clustering of the diabody could also be achieved by the dimeric PSMA antigen expressed on tumor cells. Thus, although the diabody binds to all T-cells, only those in contact with PSMA-expressing cancer cells are activated. In conclusion, the PSMA x CD3 diabody is suitable for a controlled polyclonal T-cell therapy of prostate cancer.
authors.affiliation: Department of Urology, Experimental Urology, University of Freiburg, Freiburg, Germany.
authors.forename: Patrick
authors.initials: P
authors.lastname: Bühler
authors.forename: Eszter
authors.initials: E
authors.lastname: Molnar
authors.forename: Elaine P
authors.initials: EP
authors.lastname: Dopfer
authors.forename: Philipp
authors.initials: P
authors.lastname: Wolf
authors.forename: Dorothee
authors.initials: D
authors.lastname: Gierschner
authors.forename: Ulrich
authors.initials: U
authors.lastname: Wetterauer
authors.forename: Wolfgang W A
authors.initials: WW
authors.lastname: Schamel
authors.forename: Ursula
authors.initials: U
authors.lastname: Elsässer-Beile
mesh_terms: D018033:Antibodies, Bispecific / Q000276:immunology / Q000627:therapeutic use*; D017252:CD3 Complex / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000637:transplantation; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000637:transplantation; D002118:Calcium / Q000378:metabolism; D045744:Cell Line, Tumor; D016207:Cytokines / Q000276:immunology; D053222:Fas Ligand Protein / Q000276:immunology / Q000378:metabolism; D006801:Humans; D008213:Lymphocyte Activation; D008297:Male; D054353:Perforin / Q000276:immunology / Q000378:metabolism; D017430:Prostate-Specific Antigen / Q000276:immunology*; D011471:Prostatic Neoplasms / Q000276:immunology / Q000628:therapy*; D015854:Up-Regulation
chemical_list: D018033:Antibodies, Bispecific; D017252:CD3 Complex; D016207:Cytokines; C505661:FASLG protein, human; D053222:Fas Ligand Protein; D054353:Perforin; D017430:Prostate-Specific Antigen; D002118:Calcium