TCR repertoire analysis revealed the mobilization of novel CD8+ T cell clones into Cancer-Immunity Cycle following anti-CD4 antibody administration

Depletion of CD4+ cells by anti-CD4 monoclonal antibody (anti-CD4 mAb) induces expansion of tumor-reactive CD8+ T cells and exhibits strong antitumor effects in several murine tumor models. However, whether the anti-CD4 mAb treatment activates particular or a broad variety of tumor-reactive CD8+ T cell clones is not answered. To investigate the changes of TCR repertoire induced by the anti-CD4 mAb treatment, we performed unbiased high throughput TCR sequencing in a B16F10 mouse subcutaneous melanoma model. In the B16F10 subcutaneous tumor model, CD8+ T cells in tumor, peripheral blood (PBL) and draining lymph node (dLN), and CD8+ CD44hi T cells in dLN were purified by cell sorting at day 14 post-tumor inoculation. Then, we prepared libraries from these CD8+ T cell sample and performed unbiased high throughput TCR sequencing using an IonProton next generation sequencer.