Rationally engineered therapeutic proteins with reduced immunogenicity.
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.
Tangri
Shabnam
S
Epimmune, San Diego, CA 92121, USA.
Mothé
Bianca R
BR
Eisenbraun
Julie
J
Sidney
John
J
Southwood
Scott
S
Briggs
Kristen
K
Zinckgraf
John
J
Bilsel
Pamuk
P
Newman
Mark
M
Chesnut
Robert
R
Licalsi
Cynthia
C
Sette
Alessandro
A
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
D006684:HLA-DR Antigens; D016056:Immunodominant Epitopes; D011994:Recombinant Proteins; D004921:Erythropoietin