Protein Deimmunization Platform
Therapeutic proteins often have the undesirable potential to elicit an unwanted immune response in patients. Clinical studies have shown that both human proteins (e.g. EPO, IFNα and IFNβ) and non-human proteins (e.g. staphylokinase and glucarpidase) can induce immune responses ranging from neutralizing antibodies to severe allergic reactions and even autoimmunity. Technologies employed to reduce the immunogenicity of proteins have not always proved effective and occasionally have unintended consequences such as a reduction in yield due to manufacturing issues.
T cell epitope identified and removed
Composite Protein™ technology improves upon the previous deimmunization technologies through the incorporation of EpiScreen™ to more accurately identify and prioritise removal of T cell epitopes.
Through the use of EpiScreen™ and a panel of overlapping peptides, T cell epitopes (the primary drivers of long-lived, memory based immunogenicity) are identified and ranked by magnitude and promiscuity. The T cell epitopes are then removed from the protein using proprietary in silico tools and new protein variants are designed.
Simultaneously, structure and homology analyses guide the targeting and substitution of key amino acids in order to retain the desired protein activity. Following expression and purification deimmunization of the resulting Composite Protein™ is confirmed by the EpiScreen™ time course T cell assay.
Case Study: Immunoglobulin G-degrading enzyme from Streptococcus pyogenes (IdeS)
IdeS has been identified as a potential treatment for IgG-mediated autoimmune diseases. It is a cysteine protease that specifically cleaves IgGs at the hinge region. Due to its inherent immunogenicity it required deimmunization. IdeS was successfully deimmunised using a combination of Abzena’s EpiScreen™ T Cell Epitope Mapping technology and iTope™ in silico tools. In order to demonstrate the reduction in potential immunogenicity of deimmunised IdeS, the deimmunised protein was tested in comparison to wild type IdeS in Abzena’s Episcreen™ T cell time course assay.
Above: CD4+ T cell responses were measured using Abzena’s EpiScreen™ T-cell Time Course assay. CD4+ T cells were incubated with the samples and assessed for proliferation on days 5-8. T cell responses with a stimulation index ≥1.90 (indicated by red dotted line) that were significant (p <0.05) using an unpaired, two sample Student’s t-test were considered positive. The Episcreen assay confirmed that the potential immunogenicity of the deimmunised IdeS variant was reduced compared to the wild type IdeS.
- Non-human proteins – Composite Proteins™ can be produced using one or more non-human proteins as a reference.
- New properties – novel Composite Proteins™ can be generated from protein libraries and screened for new properties.
- Different formats – Composite Proteins™ can be generated in different formats including full-length proteins, protein fragments and fusion proteins.
Working with Abzena
Abzena’s services are tailored for each project to ensure that the objectives are met or exceeded. Experienced project teams are assigned to each study focusing on progressing projects through to results in the minimum amount of time. Our clients widely regard us as professional and attentive partners who deliver quality results.
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