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)