Phototherapy Facilitates Tumor Recruitment and Activation of Natural Killer T cells for Potent Cancer Immunotherapy.

ABSTRACT

Adoptively transferred natural killer T (NKT) cells confer distinct cancer surveillance without causing obvious side effects, making them a promising candidate for cancer immunotherapy. However, their therapeutic efficacy is limited by inefficient tumor infiltration and inadequate activation in an immunosuppressive tumor microenvironment. To overcome these obstacles, we develop a strategy of using photothermal therapy (PTT) to promote the antitumor ability of adoptively transferred NKT cells. The transferred NKT cells are efficiently recruited to PTT-treated tumors in response to PTT-created inflammation. Moreover, PTT treatment promotes the activation of NKT cells and enhances the NKT cell-initiated immune cascade. As a consequence, the combined therapy of PTT plus NKT cell transfer exhibits excellent growth inhibition of local tumors. Moreover, it efficiently rejects distant tumors and elicits long-term immunological memory to prevent tumor recurrence. Overall, the current study opens new paths to the clinical translation of NKT cells for cancer immunotherapy.