Figure 2.

Some representative approaches of MNPs to turn a “cold” tumor into “hot”. (A) MNP-based magnetic hyperthermia ablation therapy is capable of inducing tumor immunogenic cell death to promote the release of antigen for DC maturation, and the subsequent CTL activation and infiltration in the tumor. (B, C) MNPs carrying immune agents such as agonists can be applied (B) for potentiating DCs or (C) for potentiating CTLs. (D) MNPs carrying immune agents such as antibodies can bind CTLs, and direct them to the tumor with an improved accumulation and infiltration by the magnetic guidance. (E) The tumor accumulation of the immune checkpoint antibody can be enhanced by the conjugation on MNPs for an improved immunosuppressive pathway modulation with fewer adverse effects. DCs, dendritic cells; MDSCs, myeloid-derived suppressor cells; CTLs, cytotoxic T lymphocytes; Tregs, regulatory T cells; TAM, tumor-associated macrophages; NKs, natural killer cells; PD-1, programmed cell death protein 1; PD-L1, programmed cell death ligand 1; CTLA-4, cytotoxic T lymphocyte-associated protein 4.