Acute lymphoblastic leukaemia (ALL) is a haematological malignancy that is characterized by the uncontrolled proliferation of immature lymphocytes. 80% of cases occur in children where ALL is well understood and treated. However it has a devastating affects on adults, where multi-agent chemotherapy is the standard of care with allogeneic stem cell transplantation for those who are eligible. New treatments are required to extend remission and prevent relapse to improve patient survival rates. We used serum profiling to compare samples from presentation adult B-ALL patients with age-and sex-matched healthy volunteer (HV) sera and identified 69 differentially recognised antigens (P ≤ 0Á02). BMX, DCTPP1 and VGLL4 showed no differences in transcription between patients and healthy donors but were each found to be present at higher levels in B-ALL patient samples than HVs by ICC. BMX plays a crucial role in the Bruton's Tyrosine Kinase (BTK) pathway which is bound by the BTK inhibitor, ibrutinib, suggesting adult B-ALL would also be a worthy target patient group for future clinical trials. We have shown the utility of proto-array analysis of B-ALL patient sera, predominantly from young adults, to help characterise the B-ALL immunome and identified a new target patient population for existing small molecule therapy.

Acute lymphoblastic leukaemia (ALL) in adults is a rare and difficult-to-treat cancer that is characterised by excess lymphoblasts in the bone marrow. Although many patients achieve remission with chemotherapy, relapse rates are high and the associated impact on survival devastating. Most patients receive chemotherapy and for those whose overall fitness supports it, the most effective treatment to date is allogeneic stem cell transplant that can improve overall survival rates in part due to a 'graft-versus-leukaemia' effect. However, due to the rarity of this disease, and the availability of mature B-cell antigens on the cell surface, few new cancer antigens have been identified in adult BALL that could act as targets to remove residual disease in first remission or provide alternative targets for escape variants if and when current immunotherapy strategies fail. We have used RT-PCR analysis, literature searches, antibody-specific profiling and gene expression microarray analysis to identify and prioritise antigens as novel targets for the treatment of adult BALL .

Results and discussions Between 6373 and 2243 peptides were identified for each cell line, but only peptides found in all replicates for each cell line analysed further. 1806 peptides were identified in all three replicates of the fibroblast cell line, while 455 and 379 peptides were common to all three replicates for the DFT1-IFNg and DFT2 cell lines respectively. Analysis of peptide length shows a preference for 8mers and 9mers in devil fibroblasts and DFT2 cells and a preference for 9mers in DFT1-IFNg. We next searched for binding motifs for the 8mers and 9mers across all cell lines and found potential anchor residues at position 3 and position 8/9, where there was a preference for hydrophobic amino acids (in particular Leucine). We then identified 61 and 55 peptides unique to DFT1-IFNg and DFT2 respectively. Conclusion This is the first study to characterise the repertoire of peptides bound to MHC molecules in contagious cancers and represents a pivotal step for understanding the immunological features of transmissible cancers. Introduction Cancer stem cells (CSCs) are more resistant to chemo-and radiation therapy than the bulk of the tumour. CSCs, surviving traditional therapies, possess self-renewal capacity and contribute to tumour re-growth. We are investigating the susceptibility of CSCs to antigen-specific killing by T cells. We generated a dataset incorporating all HLA Class I epitopes of the DU145 prostate cancer cell line. We aim to identify novel CSC epitopes which may serve as T cell targets. Material and methods We isolated HLA Class I:peptide complexes from DU145 cells by immunoaffinity precipitation and analysed the epitope sequences by liquid chromatography tandem-mass spectrometry (LC-MS/MS). We selected epitopes in the dataset which showed low gene expression in healthy tissues (www.GTexportal.org) and high predicted HLA-binding affinity (http://tools.immuneepitope.org/mhci/). DU145 CSCs were isolated based on aldehyde dehydrogenase (ALDH) activity using FACS. ALDH high and ALDH low DU145 cells were determined to have CSC or non-CSC characteristics, respectively, by in vivo tumour initiation. Gene expression of the epitopes was measured by qPCR in ALDH high and ALDH low DU145 cells. Protein expression was determined by immunofluorescence. We performed homology modelling of the HLA: peptide interfaces and quantified the binding interactions using PISA interface analysis software. We measured T cell activation by selected peptides analysing cytokine release by flow cytometry. Results and discussions We selected 42 epitopes from the DU145 dataset with low global tissue expression and predicted HLA binding percentile rank <1%. We identified 11 CSC epitopes by qPCR; 6 upregulated in ALDH high DU145 cells (e.g. TACSTD2) and 5 abundant in both ALDH high and ALDH low DU145 cells (e.g. XPO1). We identified 3 HLA:epitope complexes for which the PISA P-value indicated high affinity interface interactions. CD8 + T cells that release cytokines in response to one of these epitopes have been identified. Th...