title: Rationally engineered therapeutic proteins with reduced immunogenicity.
abstract: Chronic administration of protein therapeutics may elicit unacceptable immune responses to the specific protein. Our hypothesis is that the immunogenicity of protein drugs can be ascribed to a few immunodominant helper T lymphocyte (HTL) epitopes, and that reducing the MHC binding affinity of these HTL epitopes contained within these proteins can generate drugs with lower immunogenicity. To test this hypothesis, we studied the protein therapeutic erythropoietin (Epo). Two regions within Epo, designated Epo 91-120 and Epo 126-155, contained HTL epitopes that were recognized by individuals with numerous HLA-DR types, a property common to immunodominant HTL epitopes. We then engineered analog epitopes with reduced HLA binding affinity. These analog epitopes were associated with reduced in vitro immunogenicity. Two modified forms of Epo containing these substitutions were shown to be bioactive and nonimmunogenic in vitro. These findings support our hypothesis and demonstrate that immunogenicity of protein drugs can be reduced in a systematic and predictable manner.
authors.affiliation: Epimmune, San Diego, CA 92121, USA.
authors.forename: Shabnam
authors.initials: S
authors.lastname: Tangri
authors.forename: Bianca R
authors.initials: BR
authors.lastname: Mothé
authors.forename: Julie
authors.initials: J
authors.lastname: Eisenbraun
authors.forename: John
authors.initials: J
authors.lastname: Sidney
authors.forename: Scott
authors.initials: S
authors.lastname: Southwood
authors.forename: Kristen
authors.initials: K
authors.lastname: Briggs
authors.forename: John
authors.initials: J
authors.lastname: Zinckgraf
authors.forename: Pamuk
authors.initials: P
authors.lastname: Bilsel
authors.forename: Mark
authors.initials: M
authors.lastname: Newman
authors.forename: Robert
authors.initials: R
authors.lastname: Chesnut
authors.forename: Cynthia
authors.initials: C
authors.lastname: Licalsi
authors.forename: Alessandro
authors.initials: A
authors.lastname: Sette
mesh_terms: D000595:Amino Acid Sequence; D004921:Erythropoietin / Q000737:chemistry / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D006684:HLA-DR Antigens / Q000378:metabolism; D006801:Humans; D016056:Immunodominant Epitopes / Q000737:chemistry / Q000235:genetics; D066298:In Vitro Techniques; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011485:Protein Binding; D015202:Protein Engineering / Q000379:methods*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics* / Q000276:immunology* / Q000378:metabolism; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology
chemical_list: D006684:HLA-DR Antigens; D016056:Immunodominant Epitopes; D011994:Recombinant Proteins; D004921:Erythropoietin