title: Humanization of a chicken anti-IL-12 monoclonal antibody.
abstract: Chicken anti-IL-12 monoclonal antibodies were isolated by phage display using spleen cells from a chicken immunized with human and mouse IL-12 as a source for library construction. One of the chicken monoclonal antibodies, DD2, exhibited binding to both human and mouse IL-12 in the single-chain Fv form and also after conversion to chicken-human chimeric IgG1/lambda antibody. The chicken DD2 variable regions were humanized by transferring their CDRs and several framework amino acids onto human acceptor variable regions. In the Vlambda, six chicken framework amino acids were identified to be important for the conformation of the CDR structure by computer modeling and therefore were retained in the humanized form; likewise, five chicken amino acids in the VH framework regions were retained in the humanized VH. The affinities of humanized DD2 IgG1/lambda to human and mouse IL-12 measured by competitive binding were nearly identical to those of chicken-human chimeric DD2 IgG1/lambda. This work demonstrates that humanization of chicken monoclonal antibodies assisted by computer modeling is possible, leading to a new way to generate therapeutic humanized antibodies against antigens to which the rodent immune system may fail to efficiently raise high affinity antibodies.
authors.affiliation: Protein Design Labs, Inc., 34801 Campus Drive, Fremont, CA 94555, USA. ntsurushita@pdl.com
authors.forename: Naoya
authors.initials: N
authors.lastname: Tsurushita
authors.forename: Minha
authors.initials: M
authors.lastname: Park
authors.forename: Kanokwan
authors.initials: K
authors.lastname: Pakabunto
authors.forename: Kelly
authors.initials: K
authors.lastname: Ong
authors.forename: Anamarija
authors.initials: A
authors.lastname: Avdalovic
authors.forename: Helen
authors.initials: H
authors.lastname: Fu
authors.forename: Audrey
authors.initials: A
authors.lastname: Jia
authors.forename: Max
authors.initials: M
authors.lastname: Vásquez
authors.forename: Shankar
authors.initials: S
authors.lastname: Kumar
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000276:immunology* / Q000302:isolation & purification*; D000915:Antibody Affinity / Q000276:immunology; D000918:Antibody Specificity / Q000276:immunology*; D002645:Chickens / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007135:Immunoglobulin Variable Region / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D018664:Interleukin-12 / Q000276:immunology*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019151:Peptide Library
chemical_list: D000911:Antibodies, Monoclonal; D007135:Immunoglobulin Variable Region; D019151:Peptide Library; D018664:Interleukin-12