The biological characteristics of LAG-3 and its research progress in tumor immunity
Immunotherapy has become one of the main modalities for tumor treatment.CTLA-4 and PD-1 are the two main players in tumor immune escape.However,the low response rate of PD-1 and CTLA-4 treatments is the main challenge facing tumor immunotherapy at present.Lymphocyte activation gene 3(LAG-3),a new-generation inhibitory immune checkpoint,plays an important regulatory role in the human immune system.LAG-3 is highly expressed on various types of TIL and medi-ates tumor immune escape through multiple mechanisms.LAG-3 can also be co-expressed with PD-1 in TIL.Combined block-ade of LAG-3 and PD-1 synergistically inhibits immune escape,increases antitumor response,and enhances T cell proliferation.It has become one of the most promising immunotherapies to improve the current deficiencies in tumor immunotherapy.There-fore,it is of great significance to deeply understand the biological characteristics of LAG-3 and further explore its mechanism of action.In addition,the structure and function of LAG-3 as well as its research progress in tumor immunity are reviewed.