University of Maryland School of Medicine, Department of Otorhinolaryngology-Head and Neck Surgery, Baltimore, MD 21201, USA; CuraGen Corporation, Branford, CT 06405, USA.
Mol Immunol. 2013 Dec;56(4):819-28. doi: 10.1016/j.molimm.2013.08.003.
The role of the B7 family molecules in the regulation of the immune response is well documented. A large body of experimental evidence indicates that costimulatory molecules such as B7-1, B7-2, B7-DC, B7-H1, B7-H2, B7-H3 and B7-H4 are critical for initiation, maintenance and down-regulation of the immune response. However the immunological function of butyrophilin (BTN)-like molecules, which are a part of the expanded B7 family, is not known. Here, we demonstrate that the extracellular portion of human BTNL8 can augment Ag-induced activation of T lymphocytes. BTNL8 has two alternatively spliced forms: B7-like and BTN-like. Both isoforms of BTNL8 were expressed concurrently in various human tissues. A putative BTNL8 receptor was detected only on resting T lymphocytes. Administration of BTNL8Ig fusion protein into mice promoted production of Ag-specific IgG during the primary, but not the secondary immune responses. BTNL8 may therefore play an essential role in priming of naïve T lymphocytes.
B7 家族分子在免疫反应调节中的作用已得到充分证实。大量实验证据表明，共刺激分子如 B7-1、B7-2、B7-DC、B7-H1、B7-H2、B7-H3 和 B7-H4 对于免疫反应的启动、维持和下调至关重要。然而，BTN 样分子（属于扩展的 B7 家族的一部分）的免疫学功能尚不清楚。在这里，我们证明了人 BTNL8 的细胞外部分可以增强 Ag 诱导的 T 淋巴细胞激活。BTNL8 有两种选择性剪接形式：B7 样和 BTN 样。两种 BTNL8 同工型在各种人类组织中同时表达。在静止的 T 淋巴细胞上仅检测到推定的 BTNL8 受体。BTNL8Ig 融合蛋白给药可促进小鼠在初次而不是二次免疫反应期间产生 Ag 特异性 IgG。因此，BTNL8 可能在初始 T 淋巴细胞的启动中发挥重要作用。
