B7-H1／PD-1共刺激途径与病毒感染

B7-H1/PD-1 co-stimulatory pathway and virus infection

B7-H1及其受体PD-1是共刺激分子B7-CD28家族的重要成员。B7-H1在淋巴组织及外周非淋巴组织广泛诱导性表达，PD-1则主要表达在活化的T细胞、B细胞及髓系细胞表面。B7-H1／PD-1共刺激途径主要作用是负性调节T、B细胞的免疫反应，参与维持外周组织的免疫耐受。病毒感染可以上调B7-H1及PD-1的表达，抑制病毒特异性T细胞的免疫功能，B7-H1／PD-1途径是病毒逃避免疫监视，引发慢性感染的重要通路，因而阻断B7-H1／PD-1共刺激途径能够恢复病毒特异性T细胞的功能，清除病毒感染，这对于病毒感染的免疫治疗，尤其是病毒慢性感染的免疫治疗具有重要意义。

B7-H1 and its receptor PD-1 are important members of B7-CD28 family co-stimulatory mole- cules. B7-H1 is broadly induced in most peripheral tissues as well as lymphocytes. PD-1 is mainly expressed in T cells, B cells, and myeloid cells. B7-H1/PD-1 co-stimulatory pathway negatively regulates the immune function of T and B cells, and is involved in immune tolerance in peripheral tissue. Virus infection can upregulate BT-H1 and PD-1 expressions and lead to virus-specific T cell dysfunction, which may be an important mechanism of virus immune evasion and persistent infection. Blockade of BT-H1/PD-1 pathway can restore the impaired function of virus-specific T cells and clear virus, which may be important for virus infection immune therapy, particularly the chronic virus infection immune therapy.