TIGIT antibody with PVR competitive ability enhances cancer immunotherapy and capable of eliciting anti-tumour immune memory.

Background: T-cell immunoreceptor with immunoglobulin (Ig) and ITIM domains (TIGIT) is a checkpoint receptor thought to be involved in mediating T-cell exhaustion and dysfunction of natural killer (NK) cells in tumours and is emerging as novel promising targets in immunotherapy, however, the ligand binding and the efficacy of its antibody still need to be further explored.

Methods: Four different TIGIT antibodies in characteristics of antigen binding, in vitro effects on activated T cells, Fc region functions and tumour inhibition in animal models were compared. The antibody as monotherapy and combined with anti-PD-L1 antibody, effects on PBMC in ex vivo coculture with autologous human CRC organoids as well as PK profile were evaluated.

Results: Studies demonstrated that TIGIT antibody with PVR-competitive ability as monotherapy resulted in inhibition of tumour growth, sustained anti-tumour immune memory in tumour re-challenge mice, enhanced anti-tumour therapy in combination with anti-PD-L1. Ex vivo coculture assay suggested that TIGIT antibody treatment activated immune cells and promoted infiltration and tumour killing ability of autologous PBMC in human CRC organoids.

Conclusions: Our study broadens the knowledge of TIGIT antibody in cancer immunotherapy and may benefit future development of next-generation checkpoint inhibitors with improved clinical outcomes.