Duan Byian, Morel Laurence
Department of Pathology, Immunology, and Laboratory Medicine, University of Florida, Gainesville, FL 32610, United States.
Autoimmun Rev. 2006 Jul;5(6):403-8. doi: 10.1016/j.autrev.2005.10.007. Epub 2005 Dec 9.
B-1a cells are distinguished from conventional B cells (B2) by their developmental origin, their surface marker expression and their functions. They were originally identified as a B cell subset of fetal origin that expresses the pan-T cell surface glycoprotein, CD5. B-1a cells also differ from B2 by the expression levels of several surface markers, including IgM, IgD, CD43 and B220 [R. Berland, H.H. Wortis, Origins and functions of B-1 cells with notes on the role of CD5. Ann Rev Immunol, 20 (2002) 253-300.]. The majority of B-1a cells are located in peritoneal and pleural cavities. Compared to B2 cells, B-1a are long-lived, non-circulating, with reduced BCR diversity and affinity [A.B. Kantor, C.E. Merrill, L.A. Herzenberg, J.L. Hillson, An unbiased analysis of V-H-D-J(H) sequences from B-1a, B-1b, and conventional B cells. J Immunol, 158 (1997) 1175-1186.]. B-1a cells are largely responsible for the production of circulating IgM referred to as natural antibodies. These low affinity antibodies are polyreactive and constitute as such a first line of defense against bacterial pathogens [M.C. Carroll, A.P. Prodeus, Linkages of innate and adaptive immunity. Curr Opin Immunol, 10 (1998) 36-40.]. This polyreactivity also results into the recognition of autoantigens, which serves in the clearance of apoptosis products. The weak autoreactivity of the B-1a cells has been postulated to play a role in autoimmune pathogenesis. In addition, other characteristics, such as the production of high level of IL-10 [A. O'Garra, R. Chang, N. Go, R. Hastings, G. Haughton, M. Howard, et al. Ly-1 B (B-1) cells are the main source of B cell-derived interleukin 10. Eur J Immunol, 22 (1992) 711-717.] and enhanced antigen presentation capacities [C. Mohan, L. Morel, P. Yang, E.K. Wakeland, Accumulation of splenic B1a cells with potent antigen-presenting capability in NZM2410 lupus-prone mice. Arthritis and Rheumatism, 41 (1998) 1652-1662.], have implicated B-1a cells in autoimmunity. This review will discuss the current understandings of their role in autoimmune diseases with focus on lupus.
B-1a细胞在发育起源、表面标志物表达及功能方面与传统B细胞（B2细胞）有所不同。它们最初被鉴定为起源于胎儿的B细胞亚群，表达泛T细胞表面糖蛋白CD5。B-1a细胞在几种表面标志物的表达水平上也与B2细胞不同，包括IgM、IgD、CD43和B220[R. Berland, H.H. Wortis, B-1细胞的起源和功能以及关于CD5作用的注释。《免疫学年鉴》，20 (2002) 253 - 300]。大多数B-1a细胞位于腹膜腔和胸膜腔。与B2细胞相比，B-1a细胞寿命长、不循环，其BCR多样性和亲和力降低[A.B. Kantor, C.E. Merrill, L.A. Herzenberg, J.L. Hillson, 对B-1a、B-1b和传统B细胞V-H-D-J(H)序列的无偏分析。《免疫学杂志》，158 (1997) 1175 - 1186]。B-1a细胞在很大程度上负责产生被称为天然抗体的循环IgM。这些低亲和力抗体具有多反应性，因此构成了抵御细菌病原体的第一道防线[M.C. Carroll, A.P. Prodeus, 固有免疫和适应性免疫的联系。《当代免疫学观点》，10 (1998) 36 - 40]。这种多反应性还导致对自身抗原的识别，这有助于清除凋亡产物。据推测，B-1a细胞的弱自身反应性在自身免疫发病机制中起作用。此外，其他特征，如高水平IL-10的产生[A. O'Garra, R. Chang, N. Go, R. Hastings, G. Haughton, M. Howard等，Ly-1 B（B-1）细胞是B细胞来源的白细胞介素10的主要来源。《欧洲免疫学杂志》，22 (1992) 711 - 717]和增强的抗原呈递能力[C. Mohan, L. Morel, P. Yang, E.K. Wakeland, NZM2410狼疮易感小鼠脾脏中具有强大抗原呈递能力的B1a细胞积累。《关节炎与风湿病》，41 (1998) 1652 - 1662]，也表明B-?1a细胞与自身免疫有关。本综述将讨论目前对它们在自身免疫性疾病中作用的理解，重点是狼疮。
