日本京都大学再生医学科学研究所的一个研究小组经研究发现，对人体免疫功能有调节作用的T细胞（胸腺依赖淋巴细胞）按活力大小可分为“活性型”与“非活性型”两种。该成果发表在22日的美国免疫学杂志《免疫》电子版上。
T细胞是哺乳动物体内抑制免疫反应的淋巴细胞群。据称，研究人员在人体T细胞表面分子上使用了一种带标志的抗体，来调查T细胞的反应。结果发现T细胞对抗体的反应分为两种，一种离开了抗体，一种则与抗体紧密结合在一起。研究人员据此将其分别命名为“活性型”和“非活性型”。
研究发现，活性型T细胞对免疫反应的抑制力很强，而非活性型的抑制力则很小，不过受到相应刺激的话，非活性型可以转化成活性型。对于人类，胎儿的血液中非活性型T细胞比较多，上了年纪的老人体内则是活性型T细胞比较多。
研究人员称，自身免疫疾病和脏器移植中排斥反应的轻重与这两种T细胞的比例有直接关系，如果活性型T细胞减少，就容易患病或出现排斥反应。而如果能够控制这两种T细胞的比例，找到抑制排斥反应的方法，就有可能开发出治疗自身免疫障碍和过敏性疾病，以及抑制脏器移植过程中排斥反应的药品。（生物谷Bioon.com）
生物谷推荐原始出处：
Immunity, 21 May 2009 doi:10.1016/j.immuni.2009.03.019
Functional Delineation and Differentiation Dynamics of Human CD4+ T Cells Expressing the FoxP3 Transcription Factor
Makoto Miyara1,10,Yumiko Yoshioka1,9,Akihiko Kitoh1,9,Tomoko Shima1,9,Kajsa Wing1,Akira Niwa2,Christophe Parizot3,Cécile Taflin3,Toshio Heike2,Dominique Valeyre4,Alexis Mathian3,Tatsutoshi Nakahata2,Tomoyuki Yamaguchi1,Takashi Nomura1,Masahiro Ono1,Zahir Amoura5,6,Guy Gorochov3,6andShimon Sakaguchi1,7,8,,
1 Department of Experimental Pathology, Institute for Frontier Medical Sciences, Kyoto University, Kyoto 606-8507, Japan
2 Department of Pediatrics, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan
3 Institut National de la Santé et de la Recherche Médicale (INSERM) UMR-S 945, Laboratoire AP-HP d'immunologie cellulaire et tissulaire, H?pital Pitié-Salpêtrière, 75013 Paris, France
4 Pneumology Department, AP-HP H?pital Avicenne, 93000 Bobigny, France
5 Internal Medicine Department, AP-HP H?pital Pitié-Salpêtrière, 75013 Paris, France
6 Pierre and Marie Curie University, UPMC Paris Universitas, 75005 Paris, France
7 Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency, Kawaguchi 332-0012, Japan
8 WPI Immunology Frontier Research Center, Osaka University, Suita 565-0871, Japan
9 These authors contributed equally to this work
10 Present address: Internal Medicine Department and Institut National de la Santé et de la Recherche Médicale (INSERM) UMR-S 945, Laboratoire AP-HP d'immunologie cellulaire et tissulaire, H?pital Pitié-Salpêtrière, 75013 Paris, France
FoxP3 is a key transcription factor for the development and function of natural CD4+ regulatory Tcells (Treg cells). Here we show that human FoxP3+CD4+ Tcells were composed of three phenotypically and functionally distinct subpopulations: CD45RA+FoxP3lo resting Treg cells (rTreg cells) and CD45RAFoxP3hi activated Treg cells (aTreg cells), both of which were suppressive invitro, and cytokine-secreting CD45RAFoxP3lo nonsuppressive Tcells. The proportion of the three subpopulations differed between cord blood, aged individuals, and patients with immunological diseases. Terminally differentiated aTreg cells rapidly died whereas rTreg cells proliferated and converted into aTreg cells invitro and invivo. This was shown by the transfer of rTreg cells into NOD-scid-common -chain-deficient mice and by TCR sequence-based Tcell clonotype tracing in peripheral blood in a normal individual. Taken together, the dissection of FoxP3+ cells into subsets enables one to analyze Treg cell differentiation dynamics and interactions in normal and disease states, and to control immune responses through manipulating particular FoxP3+ subpopulations.
