Abstract
BackgroundSince most glioblastomas express both wild-type EGFR and EGFRvIII as well as HER2/neu, they are excellent targets for activated T cells (ATC) armed with bispecific antibodies (BiAbs) that target EGFR and HER2.MethodsATC were generated from PBMC activated for 14 days with anti-CD3 monoclonal antibody in the presence of interleukin-2 and armed with chemically heteroconjugated anti-CD3×anti-HER2/neu (HER2Bi) and/or anti-CD3×anti-EGFR (EGFRBi). HER2Bi- and/or EGFRBi-armed ATC were examined for in vitro cytotoxicity using MTT and 51Cr-release assays against malignant glioma lines (U87MG, U118MG, and U251MG) and primary glioblastoma lines.ResultsEGFRBi-armed ATC killed up to 85% of U87, U118, and U251 targets at effector:target ratios (E:T) ranging from 1:1 to 25:1. Engagement of tumor by EGFRBi-armed ATC induced Th1 and Th2 cytokine secretion by armed ATC. HER2Bi-armed ATC exhibited comparable cytotoxicity against U118 and U251, but did not kill HER2-negative U87 cells. HER2Bi- or EGFRBi-armed ATC exhibited 50—80% cytotoxicity against four primary glioblastoma lines as well as a temozolomide (TMZ)-resistant variant of U251. Both CD133– and CD133+ subpopulations were killed by armed ATC. Targeting both HER2Bi and EGFRBi simultaneously showed enhanced efficacy than arming with a single BiAb. Armed ATC maintained effectiveness after irradiation and in the presence of TMZ at a therapeutic concentration and were capable of killing multiple targets.ConclusionHigh-grade gliomas are suitable for specific targeting by armed ATC. These data, together with additional animal studies, may provide the preclinical support for the use of armed ATC as a valuable addition to current treatment regimens.
Highlights
Since most glioblastomas express both wild-type EGFR and EGFRvIII as well as HER2/neu, they are excellent targets for activated T cells (ATC) armed with bispecific antibodies (BiAbs) that target EGFR and HER2
Validation of MTT assay Since our previous work with armed ATC employed the 51Cr release assay, we did parallel testing to confirm the relationship between viable cell number and MTT assay signal
Does the simultaneous Use of Two BiAbs to Arm ATC improve killing glioma targets? Since there was a spectrum of expression levels of EGFR and HER2/neu on the target cells, we investigated whether simultaneous targeting using two BiAbs would improve killing
Summary
Since most glioblastomas express both wild-type EGFR and EGFRvIII as well as HER2/neu, they are excellent targets for activated T cells (ATC) armed with bispecific antibodies (BiAbs) that target EGFR and HER2. Arming anti-CD3 activated T cells (ATC) with bispecific antibodies (BiAb) that target the T cell receptor on one hand cells in vitro [10]. In our phase I clinical trial involving stage IV breast cancer patients who received activated T cells (ATC) armed with anti-CD3×anti-Her2/neu bispecific antibody (HER2Bi), high levels of circulating tumoricidal cytokines and specific cytotoxicity by PBMC were observed [10]. In an earlier trial, using targeted therapy, lymphokine activated killer (LAK) cells armed with chemically heteroconjugated bispecific antibody (anti-CD3MAb x anti-glioma MAb) in 10 patients showed promising clinical results. ATC armed with HER2Bi and/or anti-CD3×anti-EGFR (EGFRBi) produced by chemical heteroconjugation of antiCD3 (OKT3) with trastuzumab or cetuximab, respectively, offers a compelling choice for adjuvant immunotherapy following surgery and chemoradiotherapy
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
