en Genomics & Proteomics and Medical Biotechnology Genomics & Proteomics and Medical Biotechnology Original Article Original Article <div style="text-align: justify;">Conventional treatment for cancer such as surgical resection and chemotherapy can cause damage in cases with advanced cancers. Moreover, the identification of tumor-specific targets has great importance in T-cell therapies. For decades, T cell activity has been stimulated to improve anti-tumor activity. Bispecific antibodies have attracted strong interest from pharmaceutical companies, for their diagnostic and therapeutic use. Blinatumomab is a first-in-class bispecific T engager antibody for the treatment of relapsed or refractory precursor B- cell acute lymphoblastic leukemia. But, it can benefit several cases with CD19⁺ malignancies in the future. PhiC31 integrase-based vectors could selectively integrate therapeutic transgenes into pseudo-attP sites in CHO genome. In this study, production of Blinatumomab in CHO cells using this type of vectors was investigated. We evaluated the effects of histone deacetylases (HDACs) inhibitors such as sodium butyrate and valproic acid, on specific productivity and cell viability of antibody expressing cells. Although sodium butyrate increased specific productivity about 1.7-fold and valproic acid about 1.4-fold, valproic acid was found more efficient because of its less cytotoxic effect on cell growth. We examined the efficacy of expressed Blinatumomab at various effector to target (E/T) ratios. A dose-response analyses of calcein-acetoxymethyl release assay illustrated that the effective dose of expressed mAb required for antibody mediated cytotoxicity was 100 ng/ml and the expressed mAb was more effective at E/T ratios of 10:1 and 5:1. Results of this study indicated that the expressed blinatumomab can be useful for enhancing the cytotoxicity of CD3⁺ T-cells against CD19 ⁺ target cells <em>in vitro</em>.</div> BiTE, T-cell activation, refractory acute lymphoid leukemia, therapeutic anti-CD19 mAb, Blinatumomab 55 66 http://ijmcmed.org/browse.php?a_code=A-10-1469-3&slc_lang=en&sid=1 Fatemeh Naddafi fatemeh.naddafi@yahoo.com 100319475328460015999 100319475328460015999 No Pharmaceutical Sciences Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Fereidoun Mahboudi mahboudi@pasteur.ac.ir 100319475328460016000 100319475328460016000 No Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran. Maryam Tabarzad tabarzad.m@gmail.com 100319475328460016001 100319475328460016001 No Protein Technology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Zahra Aliabadi Farahani zahra_afarahani@yahoo.com 100319475328460016002 100319475328460016002 No Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran. Farshad H. Shirazi f.shirazi@sbmu.ac.ir 100319475328460016003 100319475328460016003 No Pharmaceutical Sciences Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Fatemeh Davami f_davami@pasteur.ac.ir 100319475328460016004 100319475328460016004 Yes Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran.