Deciphering the tumor antigen landscape of CD4+ T-cells during checkpoint immunotherapy

During checkpoint immunotherapy, both CD4+ and CD8+ T-cells clonally expand, are co-localised in the tumor and drive tumor regression. Here we aim to characterize tumor antigens recognized by CD4+ T-cells expanding under checkpoint immunotherapy and to explore whether these antigens are the same as for CD8+ T-cells that expand in close vicinity. We will modify our method previously developed to identify tumor antigens recognized by CD8+ T-cells. Particularly, this method relies on the use of i) an antigenpresenting cell line in which the HLA of the patient and its tumor cDNA can easily be expressed, and ii) a T-cell line with a GFP reporter signalling for Tcell receptors (TCRs) expanding in the tumor. By uniquely characterizing tumor antigens recognized by CD4+ T-cells, we will generate a broad view on the antigenic landscape associated with CD4+ T-cell expansion. We anticipate our insights will contribute to improved immunotherapy and cancer vaccination strategies