Maryam Ahmadi1, Fereidoun Mahboudi2, Samira Ahmadi2, Saeedeh Ebadat2, Fatemeh Nematpour2, Mohammad Reza Akbari Eidgahi3, Fatemeh Davami4. 1. Medical Biotechnology Department, Semnan University of Medical Sciences, Semnan, Iran; Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran. 2. Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran. 3. Medical Biotechnology Department, Semnan University of Medical Sciences, Semnan, Iran. Electronic address: mrakbari201177@yahoo.com. 4. Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran. Electronic address: f_davami@pasteur.ac.ir.
Abstract
OBJECTIVES: Several types of expression vectors have been used for recombinant protein expression in Chinese hamster ovary cells (CHO) which usually result in variable and unstable levels of expression. METHODS AND RESULTS: In this study, we have compared the mAb0014 expression level of single ORF/IRES vector and dual ORF vector in the presence and absence of phiC31 integrase targeting system. Both expression vectors contain an elongation factor 1α (EF1α) promoter upstream of LC and harboring an attB site. CHO-S cells were co-transfected with single ORF/IRES or dual ORF vectors along with a phiC31 integrase expression vector which can catalyze recombination between attB site and pseudo-attP sites presented in the mammalian genome. Our results demonstrated that dual ORF vector in the presence of phiC31 integrase expression vectors (+FC31 2P) generated more recombinant antibody in comparison to its negative control (-FC31 2P). Moreover, both of +FC31 2P and -FC31 2P cell pools yield higher recombinant protein in comparison to single ORF/IRES vector (FC31 IRES) cell pools. Stability of expression in phiC31 co-transfected cell pools (+FC31 2P and +FC31 IRES) had no considerable changes. CONCLUSIONS: Our results indicated that the dual ORF vector using integrase can support the generation of cell lines with stable transgene expression at an elevated mAb relative to single ORF/IRES vector.
OBJECTIVES: Several types of expression vectors have been used for recombinant protein expression in Chinese hamster ovary cells (CHO) which usually result in variable and unstable levels of expression. METHODS AND RESULTS: In this study, we have compared the mAb0014 expression level of single ORF/IRES vector and dual ORF vector in the presence and absence of phiC31 integrase targeting system. Both expression vectors contain an elongation factor 1α (EF1α) promoter upstream of LC and harboring an attB site. CHO-S cells were co-transfected with single ORF/IRES or dual ORF vectors along with a phiC31 integrase expression vector which can catalyze recombination between attB site and pseudo-attP sites presented in the mammalian genome. Our results demonstrated that dual ORF vector in the presence of phiC31 integrase expression vectors (+FC31 2P) generated more recombinant antibody in comparison to its negative control (-FC31 2P). Moreover, both of +FC31 2P and -FC31 2P cell pools yield higher recombinant protein in comparison to single ORF/IRES vector (FC31 IRES) cell pools. Stability of expression in phiC31 co-transfected cell pools (+FC31 2P and +FC31 IRES) had no considerable changes. CONCLUSIONS: Our results indicated that the dual ORF vector using integrase can support the generation of cell lines with stable transgene expression at an elevated mAb relative to single ORF/IRES vector.