title: Characterization of a novel humanized anti-CD20 antibody with potent anti-tumor activity against non-Hodgkin's lymphoma.
abstract: BACKGROUND
  Rituximab, a mouse Fab and human Fc chimeric antibody, has been widely used to treat Non-Hodgkin's lymphoma (NHL). However, only 48% of patients respond to the treatment and complete response rate is below 10%. Also, immunogenicity was reported in 17-20% patients receiving the treatment, making it unsuitable for long term diseases such as autoimmune disorders. It has been a hot research field to "humanize" rituximab toward improved efficacy and reduced immunogenicity.
  
  
  METHODS
  In this study, an advanced antibody humanization technology was applied to the sequence of the anti-CD20 antibody 2B8, its sequence of which was based on the original murine monoclonal antibody of rituximab in Roche. The complementarity-determining regions (CDRs) of the humanized antibodies were further optimized through computer-aided molecular dock.
  
  
  RESULTS
  Five novel humanized anti-CD20 antibodies 1-5(1635, 1534, 3637, 1634 and 1536) were generated and their immunogenicity was significantly decreased when compared to rituximab. The novel humanized anti-CD20 antibodies 1-5 retained the binding activity of their murine counterpart, as demonstrated by the fluorescence-activated cell-sorting analysis (FACS). When compared to rituximab, the humanized antibodies still have the similar properties on both complement-dependent cytotoxicity (CDC) and antibody-dependent cell-mediated cytotoxicity (ADCC). Furthermore, its anti-tumor efficacy in xenograft model is comparable to that of rituximab.
  
  
  CONCLUSIONS
  The humanized anti-CD20 antibodies 1-5 have lower immunogenicity than rituximab. And at the same time, they still retain the anti-tumor effect both in vitro and vivo.
authors.affiliation: Department of Biochemistry and Molecular Biology, Second Military Medical University, Shanghai, China.
authors.forename: Haifeng
authors.initials: H
authors.lastname: Zhang
authors.forename: Liping
authors.initials: L
authors.lastname: Song
authors.forename: Hongtu
authors.initials: H
authors.lastname: Ye
authors.forename: Lide
authors.initials: L
authors.lastname: Hu
authors.forename: Wenlu
authors.initials: W
authors.lastname: Liang
authors.forename: Datao
authors.initials: D
authors.lastname: Liu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000627:therapeutic use; D061067:Antibodies, Monoclonal, Humanized / Q000276:immunology / Q000627:therapeutic use* / Q000633:toxicity; D058846:Antibodies, Monoclonal, Murine-Derived / Q000737:chemistry / Q000276:immunology / Q000627:therapeutic use; D018951:Antigens, CD20 / Q000276:immunology*; D000970:Antineoplastic Agents / Q000276:immunology / Q000627:therapeutic use* / Q000633:toxicity; D001666:Binding Sites, Antibody; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D022801:Complementarity Determining Regions / Q000737:chemistry; D006801:Humans; D008228:Lymphoma, Non-Hodgkin / Q000188:drug therapy*; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D062105:Molecular Docking Simulation; D008969:Molecular Sequence Data; D000069283:Rituximab; D014183:Transplantation, Heterologous
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D058846:Antibodies, Monoclonal, Murine-Derived; D018951:Antigens, CD20; D000970:Antineoplastic Agents; D022801:Complementarity Determining Regions; D000069283:Rituximab