Abstract
The interaction between a CD4+ TH cell and an antigen presenting cell (APC) is a finely tuned event in adaptive immunity. The affinity is dictated by the T cell receptor (TCR) and the characteristics of antigenic peptide epitopes presented on the major histocompatibility complex class II (pMHC class II) molecules on APCs. Due to the high degree of polymorphism in MHC molecules and the vast repertoire of epitopes that may be presented on each, it is an immense challenge to predict epitopes relevant to disease and homeostasis. It would therefore be of very high value to develop a technology that allows for precise experimental identification of T cell epitopes in the absence of any prior knowledge of the relevant antigen, as long as one has access to T cells. We have developed a novel and generic combinatorial display system for MHC class II, based on phage display. Using phage display, one can probe an epitope sequence space orders of magnitude larger than any cellular or chemical system. As a proof of principle on such discovery, we have used a defined HLA-DR2b restricted human primary T cell clone with known specificity against a peptide from Mycobacterium avium sp. paratuberculosis. In a systematic approach, we investigate 1) the HLA-DR2b display level using different pIII and pIX capsid scaffolds, and 2) generate antigenic peptide candidate libraries and compare the selection performance of the same variants using the T cell clone as target.
The interaction between a CD4+ TH cell and an antigen presenting cell (APC) is a finely tuned event in adaptive immunity. The affinity is dictated by the T cell receptor (TCR) and the characteristics of antigenic peptide epitopes presented on the major histocompatibility complex class II (pMHC class II) molecules on APCs. Due to the high degree of polymorphism in MHC molecules and the vast repertoire of epitopes that may be presented on each, it is an immense challenge to predict epitopes relevant to disease and homeostasis. It would therefore be of very high value to develop a technology that allows for precise experimental identification of T cell epitopes in the absence of any prior knowledge of the relevant antigen, as long as one has access to T cells. We have developed a novel and generic combinatorial display system for MHC class II, based on phage display. Using phage display, one can probe an epitope sequence space orders of magnitude larger than any cellular or chemical system. As a proof of principle on such discovery, we have used a defined HLA-DR2b restricted human primary T cell clone with known specificity against a peptide from Mycobacterium avium sp. paratuberculosis. In a systematic approach, we investigate 1) the HLA-DR2b display level using different pIII and pIX capsid scaffolds, and 2) generate antigenic peptide candidate libraries and compare the selection performance of the same variants using the T cell clone as target.