The immune system relies on the ability to detect when cells are virally infected, or potentially tumorigenic, and to specifically eliminate these cells. This is achieved by the actions of Major Histocompatibility Complex (MHC) class I molecules, which bind small peptides from the proteolytic turnover of proteins in the cytoplasm, and present these peptides on the cell surface to T lymphocytes. Detection of viral, or non-self, peptides can stimulate the generation of potent anti-viral cytotoxic T lymphocyte responses.

The research focus of the Powis group is the function of Major Histocompatibility Complex (MHC) class I molecules. These molecules function in the immune system by binding and presenting short peptides, around 9 amino acids in length, to T lymphocytes. By this process the immune system can detect and eliminate virally infected cells, or cells that have become altered in some way, such as tumour cells.

Our current research topics in this area incude:

1. Do exosomes/extracellular vesicles (EV) play a role in antigen presentation? Exosomes/EV are small vesicles of around 50-200 nm in size, which are secreted by many cell types, including those of the immune system. They are replete with stimulatory molecules. They also express HLA-I MHC molecules, and we are now studying whether these molecules are immunologically active. We are sequencing the peptides present in these HLA-I molecules from cell lines, and also from blood to determine the overall HLA-I immunopeptidomes present in both health and disease.