title: PhiC31 integrase can improve the efficiency of different construct designs for monoclonal antibody expression in CHO cells.
abstract: OBJECTIVE
  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.
  
  
  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.
authors.affiliation: Medical Biotechnology Department, Semnan University of Medical Sciences, Semnan, Iran; Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran.
authors.forename: Maryam
authors.initials: M
authors.lastname: Ahmadi
authors.affiliation: Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran.
authors.forename: Fereidoun
authors.initials: F
authors.lastname: Mahboudi
authors.affiliation: Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran.
authors.forename: Samira
authors.initials: S
authors.lastname: Ahmadi
authors.affiliation: Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran.
authors.forename: Saeedeh
authors.initials: S
authors.lastname: Ebadat
authors.affiliation: Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran.
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Nematpour
authors.affiliation: Medical Biotechnology Department, Semnan University of Medical Sciences, Semnan, Iran. Electronic address: mrakbari201177@yahoo.com.
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Akbari Eidgahi
authors.affiliation: Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran. Electronic address: f_davami@pasteur.ac.ir.
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Davami
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000096:biosynthesis / Q000235:genetics; D001287:Attachment Sites, Microbiological; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D015870:Gene Expression; D005822:Genetic Vectors / Q000235:genetics*; D019426:Integrases / Q000096:biosynthesis / Q000235:genetics; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics; D019076:Transgenes
chemical_list: D000911:Antibodies, Monoclonal; D011994:Recombinant Proteins; D019426:Integrases
keywords: Chinese hamster ovary (CHO); Dual promoter vector; PhiC31; Site-specific recombination