Efficacy of natural killer T and gammadelta T cells in mesothelin-targeted immunotherapy of pancreatic cancer

Current pancreatic cancer immunotherapy focused on alphabeta (αβ) T cells, either through CD3-engaged bispecific antibodies or CAR-T. Despite their promise, dose-limited toxicity (DLT) remains a challenge in clinical practice. In light of these concerns, there is a growing interest in exploring alternative T cell types, natural killer T (NKT) cells and gammadelta (γδ) T cells, that possess the capacity to lyse tumors while potentially offering a safer therapeutic profile with fewer side effects. These cells present a compelling alternative that warrants a comprehensive evaluation of their therapeutic potential and safety profile. This study employed a MSLN/CD3 bispecific antibody to compare the anti-tumor activity of NKT and γδT cells with peripheral blood mononuclear cells (PBMCs) as controls, both <i>in vitro</i> and <i>in vivo</i>. This study demonstrated that MSLN/CD3 BsAb effectively activated and recruited PBMCs, NKT and γδT. Furthermore, under the influence of MSLN/CD3 BsAb, γδT and NKT cells exhibited notably superior anti-tumor activity compared to PBMCs, both <i>in vitro</i> and <i>in vivo</i>, while demonstrating low cytokine release. γδT cells showed almost negligible toxic side effects. In addition, the systemic administration of NKT and γδT cells activators, α-galactosylceramide (α-GalCer) and Zoledronate, could enhance the anti-tumor effect of MSLN/CD3 bsAb, with no apparent toxicity. NKT and γδT cells are promising synergistic therapeutic cell types that may overcome the limitations of CD3 bispecific antibodies in pancreatic tumor treatments, offering a new perspective for clinical applications in immunotherapy.