title: Development and identification of fully human scFv-Fcs against Staphylococcus aureus.
abstract: Staphylococcus aureus, a gram-positive pathogen, causes many human infections. Methicillin-resistant S. aureus (MRSA) is the most common drug-resistance bacteria. Nearly all MRSA bacteria are resistant to several drugs. Specific antibodies are the main components of the host's humoral immunity, and play a significant role in the process of the host's resistance to bacterial infection.
  
  
  
  A single-chain variable fragment (scFv) library was constructed using mRNA from the peripheral blood mononuclear cells of S. aureus infected volunteers. After the scFv library DNA was transformed into Escherichia coli TG1, ~1.7 × 10(7) independent clones with full-length scFv inserts. The scFv library was screened by phage display for three rounds using S. aureus as an antigen. The single clones were chosen at random and the scFvs were expressed for enzyme-linked immunosorbent assay (ELISA) assessment. Approximately 50 % of the clones were positive with good binding activity to S. aureus. To improve the stability of scFvs, scFv-fragment crystallizable regions (-Fcs) were constructed and expressed in E. coli DH5α. The expressed scFv-Fcs were purified and identified by western blot. These antibodies were further characterized and analyzed for bioactivity. The results showed that the expression level and folding of scFv-Fcs induced at 25 °C without isopropyl β-D-1-thiogalactopyranoside (IPTG) were higher than that induced at 32 °C with 1.0 mmol/L IPTG. scFv-Fcs had good bioactivity and could specifically bind with S. aureus.
  
  
  
  scFv-Fcs against S. aureus were successfully constructed and are good candidates for the development of future adjunctive therapy for severe S. aureus infections.
authors.affiliation: The School of Basic Medical Sciences, Sichuan medical university, Room 218, Hanguang building, No 319, Zhongshan road, Luzhou, Sichuan, 646000, China.
authors.forename: Siji
authors.initials: S
authors.lastname: Nian
authors.affiliation: The School of Basic Medical Sciences, Sichuan medical university, Room 218, Hanguang building, No 319, Zhongshan road, Luzhou, Sichuan, 646000, China.
authors.forename: Tong
authors.initials: T
authors.lastname: Wu
authors.affiliation: The School of Basic Medical Sciences, Sichuan medical university, Room 218, Hanguang building, No 319, Zhongshan road, Luzhou, Sichuan, 646000, China.
authors.forename: Yingchun
authors.initials: Y
authors.lastname: Ye
authors.affiliation: The School of Basic Medical Sciences, Sichuan medical university, Room 218, Hanguang building, No 319, Zhongshan road, Luzhou, Sichuan, 646000, China.
authors.forename: Xu
authors.initials: X
authors.lastname: Wang
authors.affiliation: The School of Basic Medical Sciences, Sichuan medical university, Room 218, Hanguang building, No 319, Zhongshan road, Luzhou, Sichuan, 646000, China.
authors.forename: Wenfeng
authors.initials: W
authors.lastname: Xu
authors.affiliation: The School of Basic Medical Sciences, Sichuan medical university, Room 218, Hanguang building, No 319, Zhongshan road, Luzhou, Sichuan, 646000, China. yuanqing_ok@yahoo.com.
authors.forename: Qing
authors.initials: Q
authors.lastname: Yuan
mesh_terms: D000918:Antibody Specificity / Q000276:immunology; D061505:Cell Surface Display Techniques; D004926:Escherichia coli / Q000235:genetics; D006801:Humans; D056724:Immunity, Humoral; D007167:Immunotherapy / Q000379:methods* / Q000639:trends; D007963:Leukocytes, Mononuclear / Q000276:immunology* / Q000382:microbiology; D055624:Methicillin-Resistant Staphylococcus aureus / Q000276:immunology*; D015202:Protein Engineering; D055550:Protein Stability; D057127:Single-Chain Antibodies / Q000378:metabolism*; D013203:Staphylococcal Infections / Q000276:immunology* / Q000628:therapy
chemical_list: D057127:Single-Chain Antibodies
keywords: Fragment crystallizable regions; Phage display; Single-chain variable fragment; Staphylococcus aureus; scFv-Fc