犬周邊血液淋巴球和淋巴激素活化殺手細胞中含NKp30 mRNA之CD8+ 細胞群具有自然殺手細胞毒殺能力

Abstract

NK ( Natural killer ) 細胞為先天性免疫反應中重要的一員，可快速有效的認識並清除受病毒感染之細胞和腫瘤細胞，此細胞之活化主要是來自表面抑制型接受器和活化型接受器的信息調控，現今在許多物種中已有很多不同種類之NK細胞接受器被發現，如KIR, NCRs, ILT/ILR, 2B4, CD94/NKG2, NKG2D, Ly49, NKR-P1等等。但是目前為止，和犬NK細胞表面抗原或表面接受器相關的文獻非常有限，而本論文利用RT-PCR、3’RACE和DNA定序等方式，第一個於犬PBL和LAK中鑑定出NKp30 mRNA，犬NKp30結構和人類及大鼠之NKp30類似。我們同時在犬PBL和LAK中，利用flow cytometer鑑定出一群CD8+ 細胞表現T細胞抗原，包括CD3和α/βTCR，且由real-time PCR的結果證實此細胞群含有較高之NK細胞接受器或抗原之mRNA之表現，如NKp30、NKp44、NKG2D、2B4、CD16和CD56，且這一群細胞具有較CD8-細胞為高的NK細胞毒殺能力。此群細胞未在其他動物包括人類被報告過，為犬血液中特有之細胞。

Natural Killer (NK) cells are important effectors of the innate immune response. The function of NK cells is regulated by a balance between signals transmitted by activating and inhibitory receptors. Many types of inhibitory and activating NK cell receptors in the mammals have been identified, such as KIR, NCRs, ILT/ILR, 2B4, CD94/NKG2, NKG2D, Ly49, NKR-P1, and others. As for canine species, very little information is available on the inhibitory or activating NK receptors responsible for triggering natural cytotoxicity. In this study, we have identified and sequenced the full length of canine NKp30 mRNA from dog PBL and LAK. We have also discovered a subset of canine CD8+ cells from PBL and LAK that expressed CD3 and TCR a/b, containing higher NKp30 and other NK cell-related receptors mRNA than CD8- cells, including NKp44, NKG2D, 2B4, CD16 and CD56. This subset showed significantly higher NK activity comparing to CD8- cells. This subset has never been reported in other mammals, including human. It is a unique subset of cells in dogs. This finding is useful for the study on canine NK cell receptors.