Anti-Human PD-1 antibody (Pemb

Pembrolizumab (MK-3475)是一种抑制 PD-1 受体的人源化单克隆抗体，是一个 HER2 二聚化抑制剂类，它会削弱 HER2 与 HER 家族其他成员结合的能力。Pembrolizumab是一种抗PD-1疗法，通过阻断PD-1（程序性死亡受体-1）受体来发挥作用（作用机制），这有助于阻止癌细胞躲避免疫系统，从而减少肿瘤生长。

Pembrolizumab (MK-3475) is a humanized monoclonal antibody inhibiting the PD-1 receptor and the first in the class of agents called the HER2 dimerization inhibitors that impairs the ability of HER2 to bind to other members of the HER family.Pembrolizumab is an anti-PD-1 therapy that works (mechanism of action) by blocking the PD-1 (programmed death receptor-1) receptor, which helps it stop cancer cells from hiding from the immune system, resulting in decreased tumor growth.

在过去的几年里，癌症免疫疗法一直伴随着有希望的结果。程序性细胞死亡蛋白1（Programmed Cell Death Protein 1，PD-1）通过调节T细胞活性、激活抗原特异性T细胞凋亡和抑制调节性T细胞凋亡，在抑制免疫应答和促进自身免疫耐受中发挥重要作用。程序性细胞死亡配体1（Programmed Cell Death Ligand 1，PD-L1）是一种跨膜蛋白，被认为是免疫应答的共抑制因子，它能与PD-1联合收割机结合，减少PD-1阳性细胞的增殖，抑制其细胞因子分泌，诱导细胞凋亡。PD-L1还在各种恶性肿瘤中发挥重要作用，它可以减弱宿主对肿瘤细胞的免疫反应。基于这些观点，PD-1/PD-L1轴负责癌症免疫逃逸，并对癌症治疗产生巨大影响。

PD-1（programmed cell death protein 1）是程序性死亡受体1，是活化的T细胞表达的免疫检查点受体，是一种重要的免疫抑制分子。PD-1通过向下调节免疫系统对人体细胞的反应，以及通过抑制T细胞炎症活动来调节免疫系统并促进自身耐受。这可以预防自身免疫疾病，但它也可以防止免疫系统杀死癌细胞。 PD-L1是PD-1的配体，PD-L1与免疫系统的抑制有关，可以传导抑制性的信号。肿瘤细胞也可以表达PD-L1，PD-1和PD-L1一旦结合便会向T细胞传递负向调控信号，导致T细胞无法识别癌细胞，肿瘤细胞从而实现“免疫逃逸”。 PD-1可表达在T细胞、B细胞等免疫细胞表面。不过在T细胞未活化时，几乎是不表达PD-1的，仅在T细胞活化之后，PD-1才表达在T细胞表面。 PD-L1除了会表达在肿瘤表面，参与免疫逃逸，还会在IFN-γ刺激下，表达在抗原提呈细胞（DC细胞、巨噬细胞等），以及血管内皮细胞的表面。

Cancer immunotherapy has been accompanied by promising results over the past few years. Programmed Cell Death Protein 1 (PD-1) plays a vital role in inhibiting immune responses and promoting self-tolerance through modulating the activity of T-cells, activating apoptosis of antigen-specific T cells and inhibiting apoptosis of regulatory T cells. Programmed Cell Death Ligand 1 (PD-L1) is a trans-membrane protein that is considered to be a co-inhibitory factor of the immune response, it can combine with PD-1 to reduce the proliferation of PD-1 positive cells, inhibit their cytokine secretion and induce apoptosis. PD-L1 also plays an important role in various malignancies where it can attenuate the host immune response to tumor cells. Based on these perspectives, PD-1/PD-L1 axis is responsible for cancer immune escape and makes a huge effect on cancer therapy. This review is aimed to summarize the role of PD-1 and PD-L1 in cancer, looking forward to improve the therapy of cancer.