Prostate cancer is the most common noncutaneous malignancy in men.
The prostate stem cell Ag (PSCA) is a promising target for immunotherapy of advanced disease. Based on a novel mAb directed to PSCA, we established and compared a series of murine and humanized anti-CD3-anti-PSCA single-chain bispecific Abs. Their capability to redirect T cells for killing of tumor cells was analyzed. During these studies, we identified a novel bispecific humanized Ab that efficiently retargets T cells to tumor cells in a strictly Ag-dependent manner and at femtomolar concentrations. T cell activation, cytokine release, and lysis of target cells depend on a cross-linkage of redirected T cells with tumor cells, whereas binding of the anti-CD3 domain alone does not lead to an activation or cytokine release. Interestingly, both CD8+ and CD4+ T cells are activated in parallel and can efficiently mediate the lysis of tumor cells. However, the onset of killing via CD4+ T cells is delayed. Furthermore, redirecting T cells via the novel humanized bispecific Abs results in a delay of tumor growth in xenografted nude mice.
Written by:
Feldmann A, Arndt C, Töpfer K, Stamova S, Krone F, Cartellieri M, Koristka S, Michalk I, Lindemann D, Schmitz M, Temme A, Bornhäuser M, Ehninger G, Bachmann M. Are you the author?
Institute of Immunology, Medical Faculty Carl Gustav Carus, TU Dresden, 01307 Dresden, Germany.
Reference: J Immunol. 2012 Sep 15;189(6):3249-59.
doi: 10.4049/jimmunol.1200341
PubMed Abstract
PMID: 22875801
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