EpiScreen® 2.0 MAPPs: MHC Class II Associated Peptide Proteomics

EpiScreen® 2.0 MAPPs detects and identifies MHC Class II bound peptides processed and presented by dendritic cells (DCs) from therapeutic proteins/mAbs.

Combined with our ex vivo T cell epitope mapping assay, peptides can be identified that are recognized by CD4+ T cells with the potential to trigger an immune cascade, causing T cell proliferation and leading to anti-drug antibody formation.

Together these technologies provide an approach to designing biopharmaceutical product candidates with reduced risk of immunogenicity. Ideal for use:

  • To assess the relative immunogenicity potential of new product candidates with known anti-drug activity (ADA) inducers.
  • With pharmacologically active products that negatively impact ex vivo T cell functional methods.
  • With large/complex product candidates to better inform ex vivo T cell epitope mapping assay design.
  • As a pre-filter for putative T cell epitopes – more predictive than in silico methods.
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MAPPS assay overview

CD14 positive mononuclear cells are purified from PBMC and differentiated into immature DCs, loaded with test proteins and then matured. The DCs take up and process the proteins, presenting them as linear peptides bound in the groove of MHC class II. The DCs are lysed and MHC class II bound peptide complexes are captured by immunoprecipitation using a pan-HLA-DR antibody. Naturally processed and presented peptides, from the test sample, are eluted from the captured MHC molecules for subsequent analysis by nano-LC-MS/MS.

Eluted peptides are identified using a common search algorithm and an in-house database. Identified peptides typically occur as different length variants. These variants share the same core HLA-DR binding motif and effectively form a cluster. Eluted peptides are analysed using iTope-AI and interrogated against the TCED™ database to identify possible epitopes.

Peptides presented from the test sample can be run through an EpiScreen® 2.0 T Cell Epitope Mapping Assay to identify those epitopes that bind T cell receptors and trigger an activation cascade causing T cell proliferation.

MAPPs assays have been used by Abzena in a collaboration with the FDA to study the immunogenicity of the Factor VIIa analogue Vatreptacog Alfa.

MAPPs assays are also available for MHC class I presentation.