27.在腫瘤微環境(tumor microenvironment)中,下列何者是最不具免疫抑制性的分子或細胞? (A)programmed death-1(PD-1) (B)調節性T細胞(regulatory T cell, Treg) (C)M1巨噬細胞(M1 macrophage) (D)interleukin 10(IL-10)