Proefschrift

Bioorthogonal chemistry to unveil antigen processing events

The research described in this thesis focused on the use of bioorthogonal antigens to investigate immunological processes in antigen presenting cells. Bioorthogonal antigens are antigenic proteins produced through recombinant expression in a methionine auxotrophic E. coli strain.

Auteur: T. van Leeuwen
Datum: 23 november 2023
Links: Thesis in Leiden Repository

This allows for the replacement of methionine residues with the bioorthogonal non-canonical amino acid, azidohomoalanine (Aha), that resembles methionine. Aha contains an azide group that enables the selective and rapid visualization or enrichment of the antigen after a biological experiment using alkyne-modified fluorophores or alkyne-containing resins, respectively, via copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC). The research involved studying the effects of post-translational modifications (PTMs), antigen complexation and glycosylation of antibodies in immune complexes on the uptake, proteolysis, and T cell activation by dendritic cells (DCs) of Aha-containing antigens. Additionally, a new method was developed to enrich low abundant bioorthogonal antigenic fragments from complex mixtures. This method can be used in future studies to identify processed Aha-containing fragments from immune cells that are preserved for T cell presentation.