B7S1, a novel candidate for anti-tumor checkpoint blockade immunotherapy

• 来源期刊: 中国科学（生命科学）
• 年，卷（期）: 2018,（9）
• 页码范围: 1132-1134
• 页数: 3页
• 语种: 中文

摘要

Antigen-specific CD8+ T cells play a critical role in eradicating transformed or virally infected cells.Upon recognition of cancerous or viral originated peptides,presented by antigen-presenting ceils (APCs) in the form of peptide-MHC class I complex,CD8+ T cells become activated,rapidly and extensively proliferate and differentiate into functionally competent effector cells.Following successfully and timely clearing transformed or virally infected cells,the majority of effector CD8+ T cells die of apoptosis.Concomitantly a small fraction (around 5％-10％) of effector CD8+ T cells survive and progressively differentiate into long-lived and self-renewable memory CD8+ T cells.When reencountering the same cancerous or viral antigens,these memory T cells will rapidly respond by enhanced proliferation,cytokine production and cytolytic activities,leading to the accelerated clearance of these antigens.However,in the scenarios of established chronic viral infection and tumor,viral or tumor antigen-specific CD8+ T cells generally fail to differentiate into characteristic memory cells.Instead,these cells exhibit a distinct differentiation state,called "exhaustion".In contrast to fully functional effector CD8+ T cells or memory CD8+ T cells,exhausted CD8+ T cells progressively and fundamentally lose effector functions,including secretion of multiple cytokines,release of cytolytic components and proliferative potential and are more prone to die of apoptosis.