RT Journal Article
SR Electronic
T1 Preclinical Studies Comparing Different Bispecific Antibodies for Redirecting T cell Cytotoxicity to Extracellular Antigens on Prostate Carcinomas
JF Anticancer Research
JO Anticancer Res
FD International Institute of Anticancer Research
SP 43
OP 52
VO 25
IS 1A
A1 HILLARY E. LUM
A1 MENDY MILLER
A1 PAMELA A. DAVOL
A1 RYAN C. GRABERT
A1 JAMES B. DAVIS
A1 LAWRENCE G. LUM
YR 2005
UL http://ar.iiarjournals.org/content/25/1A/43.abstract
AB Introduction: Bispecific antibodies (BiAbs) are used to enhance targeting of T cells and other cytotoxic agents to tumors while minimizing non-specific tissue toxicities. This study compares the targeting efficacy of 3 BiAbs derived from chemically heteroconjugating a T cell-directed monoclonal antibody (mAb) to 9184, 9187 or 9189, which are mAbs directed at extracellular antigens expressed on human prostate carcinoma cell lines. Materials and Methods: 9184 (anti-Her2/neu), 9187 (anti-gp55) and 9189 (anti-gp42) were each heteroconjugated to anti-CD3 to produce BiAbs capable of binding to (“arming”) anti-CD3 activated T cells (ATC) and redirecting their cytotoxicity to prostate cancer cells expressing the respective antigen. ATC from cancer patients and/or normal subjects were armed with each BiAb and tested in co-cultures with PC-3, DU 145, and LNCaP cells for binding, cytotoxicity, and cytokine secretion. Results: All 3 tumor-directed mAbs bound to each of the prostate cancer cell lines. ATC armed with 9184Bi statistically augmented cytotoxicity directed at PC-3 and increased IFN-Á, TNF-α, and GM-CSF secretion as well as induced IFN-Á EliSpots above that seen for 9187Bi, 9189Bi, ATC alone or ATC armed with an irrelevant BiAb. 9184Bi-armed ATC mediated significant cytotoxicity against LNCaP and DU 145 cells as well. When we armed ATC from 6 cancer patients with 9184Bi, 9184Bi markedly enhanced cytotoxicity of ATC from 5 of the 6 patients. Conclusion: Arming ATC with BiAbs augments cytotoxicity directed at prostate cancer lines expressing the target antigens. Arming with 9184Bi was the most effective at redirecting cytotoxicity at PC-3 cells and inducing cytokine secretion. As an alternative to mAb therapy with anti-HER2, the HER2 antigen may provide a suitable target for redirecting anti-cancer immune cells, immunobiologicals, or other agents to HRPC.