Antibody landscape of C57BL/6 mice cured of B78 melanoma via immunotherapy

Antibodies can play an important role in innate and adaptive immune responses against cancer, and in preventing infectious disease. Using a high-density whole-proteome peptide array, we assessed potential protein-targets for antibodies found in sera of immune mice that were previously cured of their melanoma through a combined immunotherapy regimen with long-term memory. Using flow cytometry, immune sera showed strong antibody-binding against melanoma tumor cell lines. Sera from 6 of these cured mice were analyzed with this high-density, whole-proteome peptide array to determine specific antibody-binding sites and their linear peptide sequence. We identified thousands of peptides that were targeted by 2 or more of these 6 mice and exhibited strong antibody binding only by immune, not naive sera. Confirmatory studies were done to validate these results using 2 separate ELISA-based systems. To the best of our knowledge, this is the first study of the "immunome" of protein-based epitopes that are recognized by immune sera from mice cured of cancer via immunotherapy. ### Competing Interest Statement RSP, BG & JP are all employees of Nimble Therapeutics, the producer of the high-density peptide arrays used for this research. Other than these affiliations, the authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.