Direct analysis of HLA/HER-2 peptide epitopes

Background T cells recognize cancer cells via human leukocyte antigen (HLA)/peptide complexes, and class I HLA restricted tumor infiltrating T cells correspond to favorable prognoses in several cancers, including ovarian cancer. Cancerspecific HLA/peptide complexes therefore represent tumor cell surface biomarkers, and the accurate identification of HLA/peptide targets is a prerequisite for the development of T cell therapies. Potential class I HLA presented peptide fragments of human epidermal growth factor receptor 2 (HER-2) have been identified using both predictive algorithms and immunologic testing of HER-2 candidate peptides, including the controversial HER-2 peptide known as E75. Here, HLA were harvested directly from ovarian cancer cells and their peptide cargo assessed in order to determine which HER-2 peptides, including E75, represent true HLA tumor ligands.