0000000000264171
AUTHOR
Martina Fatho
Exome Sequencing to Predict Neoantigens in Melanoma
Abstract The ability to use circulating peripheral blood cells and matched tumor sequencing data as a basis for neoantigen prediction has exciting possibilities for application in the personalized treatment of cancer patients. We have used a high-throughput screening approach, combining whole-exome sequence data, mRNA microarrays, and publicly available epitope prediction algorithm output to identify mutated proteins processed and displayed by patient tumors and recognized by circulating immune cells. Matched autologous melanoma cell lines and peripheral blood mononuclear cells were used to create mixed lymphocyte tumor cell cultures, resulting in an expansion of tumor-reactive T cells to u…
Melanomas resist T-cell therapy through inflammation-induced reversible dedifferentiation.
Adoptive cell transfer therapies (ACTs) with cytotoxic T cells that target melanocytic antigens can achieve remissions in patients with metastatic melanomas, but tumours frequently relapse. Hypotheses explaining the acquired resistance to ACTs include the selection of antigen-deficient tumour cell variants and the induction of T-cell tolerance. However, the lack of appropriate experimental melanoma models has so far impeded clear insights into the underlying mechanisms. Here we establish an effective ACT protocol in a genetically engineered mouse melanoma model that recapitulates tumour regression, remission and relapse as seen in patients. We report the unexpected observation that melanoma…
The response of autologous T cells to a human melanoma is dominated by mutated neoantigens
Our understanding of pathways leading to antitumor immunity may depend on an undistorted knowledge of the primary antigenic targets of patients' autologous T cell responses. In the melanoma model derived from patient DT, we applied cryopreserved short-term autologous mixed lymphocyte–tumor cell cultures (MLTCs) in combination with an IFN-γ enzyme-linked immunospot (ELISPOT) assay to cDNA expression screening. We identified three previously unknown peptides processed from melanosomal proteins tyrosinase (presented by HLA-A*2601 and -B*3801) and gp100 (presented by HLA-B*07021) and five neoantigens generated by somatic point mutations in the patient's melanoma. The mutations were found in the…
A bicistronic vector backbone for rapid seamless cloning and chimerization of αβT-cell receptor sequences.
To facilitate preclinical testing of T-cell receptors (TCRs) derived from tumor-reactive T-cell clones it is necessary to develop convenient and rapid cloning strategies for the generation of TCR expression constructs. Herein, we describe a pDONR™221 vector backbone allowing to generate Gateway™ compatible entry clones encoding optimized bicistronic αβTCR constructs. It harbors P2A-linked TCR constant regions and head-to-head-oriented recognition sites of the Type IIS restriction enzymes BsmBI and BsaI for seamless cloning of the TCRα and TCRβ V(D)J regions, respectively. Additional well-established TCR optimizations were incorporated to enhance TCR functionality. This included replacing of…