Preparation of a Plasma-Induced Dendritic Cell Vaccine and its Anti-Tumor Immunity in a Murine Model of Melanoma

Dendritic cell (DC) vaccines play an important role in anti-tumor immunotherapy. Tumor-associated cells or cytokines in the tumor microenvironment (TME) can inhibit the antigen-presenting function of DC. Immunogenic cell death (ICD) can enhance the uptake and presentation of tumor antigens by DC. This study investigates the maturation mechanism of DC induced by low-temperature plasma (LTP), as well as the therapeutic and protective effects of LTP-induced DC vaccine in a tumor model. DC2.4 that is co-cultured with LTP-treated B16F10 (LTP-B16) or with these supernatants exhibited decreased phagocytic activity, increased production of cytokines (IL-12, IL-6, TNF-α, and IL-1β), and increased expression of cell surface activation markers (CD80, CD86, and MHC II). The expression of CD80⁺/CD86⁺ is decreased after pre-treatment with TLR4 and NF-κB (p65) inhibitors, respectively. In vivo, trials indicated that the LTP-induced DC vaccine-induced anti-tumor immunity and, when combined with cisplatin, synergistically reduced tumor growth.