Dono Mariella, Burgio Vito Lelio, Colombo Monica, Sciacchitano Salvatore, Reverberi Daniele, Tarantino Vincenzo, Cutrona Giovanna, Chiorazzi Nicholas, Ferrarini Manlio
S.C. Oncologia Medica C, Istituto Nazionale per la Ricerca sul Cancro, Genova, Italy.
Eur J Immunol. 2007 Aug;37(8):2138-47. doi: 10.1002/eji.200636887.
This study describes a CD5+ B cell that differs from the majority of the CD5+ B cells from human tonsils. This cell, isolated from in vivo activated B cells, expressed activation markers and featured a CD23-, IgMhigh, IgDlow surface phenotype, responded to T cell-independent type-2 antigens in vitro, and was detected in the subepithelial (SE) areas, the tonsil equivalent of the splenic marginal zone (MZ). Most of the cells utilized unmutated Ig VH genes, although cells with mutated genes also were found, a finding confirmed by single-cell studies. Mutated sequences were more frequent in suspensions enriched for CD27+ cells. Repeated VDJ gene sequences were observed in different molecular clones from the same cell suspension, suggesting in situ expansion. These CD5+ B cells seem to share features with previously characterized tonsil CD5- SE B cells and differ from the majority of tonsil CD5+ B cells, which have the surface phenotype of follicular mantle B cells, lack activation markers, do not respond to T cell-independent antigens, and utilize unmutated VH genes. These data are discussed considering the present views on the origin of B cell subset populations and the relationships between MZ and B1 cells.
本研究描述了一种与来自人类扁桃体的大多数CD5⁺ B细胞不同的CD5⁺ B细胞。这种细胞从体内活化的B细胞中分离出来，表达活化标志物，具有CD23⁻、IgM高、IgD低的表面表型，在体外对非T细胞依赖性2型抗原作出反应，并在扁桃体中相当于脾边缘区（MZ）的上皮下（SE）区域被检测到。大多数细胞利用未突变的Ig VH基因，不过也发现了带有突变基因的细胞，单细胞研究证实了这一发现。在富集CD27⁺细胞的悬液中，突变序列更为常见。在来自同一细胞悬液的不同分子克隆中观察到重复的VDJ基因序列，提示原位扩增。这些CD5⁺ B细胞似乎与先前鉴定的扁桃体CD5⁻ SE B细胞具有共同特征，并且不同于大多数扁桃体CD5⁺ B细胞，后者具有滤泡套B细胞的表面表型，缺乏活化标志物，对非T细胞依赖性抗原无反应，并利用未突变的VH基因。结合目前关于B细胞亚群起源以及MZ和B1细胞之间关系的观点对这些数据进行了讨论。
