T-cell dependent immunogenicity of protein therapeutics: Preclinical assessment and mitigation

Abstract

Protein therapeutics hold a prominent and rapidly expanding place among medicinal products. Purified blood products, recombinant cytokines, growth factors, enzyme replacement factors, monoclonal antibodies, fusion proteins, and chimeric fusion proteins are all examples of therapeutic proteins that have been developed in the past few decades and approved for use in the treatment of human disease. Despite early belief that the fully human nature of these proteins would represent a significant advantage, adverse effects associated with immune responses to some biologic therapies have become a topic of some concern. As a result, drug developers are devising strategies to assess immune responses to protein therapeutics during both the preclinical and the clinical phases of development. While there are many factors that contribute to protein immunogenicity, T cell- (thymus-) dependent (Td) responses appear to play a critical role in the development of antibody responses to biologic therapeutics. A range of methodologies to predict and measure Td immune responses to protein drugs has been developed. This review will focus on the Td contribution to immunogenicity, summarizing current approaches for the prediction and measurement of T cell-dependent immune responses to protein biologics, discussing the advantages and limitations of these technologies, and suggesting a practical approach for assessing and mitigating Td immunogenicity.

Keywords: 50% inhibitory concentration; ADA; ALN; APC; CFSE; Cell-mediated immunity; ELISA; ELISpot; FPX; FVIII; HLA; IC(50); IEDB; Immune Epitope Database Analysis Resource; Immunogenicity;; MHC; ORG; PBMC; Quality-by-Design;; SFC; T; T cell receptor; T cell;; T-cell dependent, thymus dependent; T-cell independent; TCR; Td; Ti; Treg; aTreg; adaptive regulatory T cells; anti-drug antibodies; antigen-presenting cells; artificial lymph node; carboxyfluorescein succinimidyl ester; enzyme-linked immunosorbent assay; enzyme-linked immunosorbent spot-forming; factor VIII; human leukocyte antigen; iTreg; induced regulatory T cells; major histocompatibility complex; nTregs; natural regulatory T cells; peripheral blood mononuclear cells; recombinant Fc fusion protein; regulatory T cells; spot-forming cells; thymus; unmodified original epitopes.