Reichert R A, Gallatin W M, Weissman I L, Butcher E C
J Exp Med. 1983 Mar 1;157(3):813-27. doi: 10.1084/jem.157.3.813.
Germinal center B cells (GCLC) are a discrete population of antigen-activated lymphoblasts that lack surface IgD and express abundant cell surface binding sites for peanut agglutinin (PNA). These phenotypic features render GCLC easily distinguishable from nearly all plasma cells, T cells, and unstimulated B cells, and have enabled us to identify and isolate GCLC from antigen-stimulated murine lymphoid organs. We have examined the migratory properties of these lymphoblasts in (a) short-term in vivo homing studies, and (b) an in vitro assay of lymphocyte binding to post-capillary, high endothelial venules (HEV) in frozen sections of Peyer's patches and peripheral lymph nodes. In the in vivo experiments, intravenously injected GCLC failed to migrate in significant numbers to peripheral lymphoid organs in comparison with T cells or IgD+ B cells. In the in vitro binding assay, GCLC did not adhere to HEV in either Peyer's patch or peripheral node sections. A variety of factors, such as preferential sequestration in the liver, may operate in vivo to influence the localization of these cells. However, their nearly total failure to migrate into lymphoid organs can best be explained by their inability to recognize and adhere to the specialized HEV which normally mediate the emigration of recirculating lymphocytes from the blood into these sites. The concept that GCLC fail to express functional homing receptors for HEV has been further supported by studies using MEL-14, a monoclonal antibody that appears to recognize the lymphocyte surface receptor for peripheral node HEV: In contrast to most peripheral lymphocytes, GCLC fail to bind MEL-14. These migratory and endothelial-recognition properties of GCLC, when viewed in the context of the possible role of these cells as precursors of plasma cells and/or memory B cells, have led us to propose that the inability of GCLC to recognize HEV may be transient and related to a phase of sessile B cell differentiation.
生发中心B细胞（GCLC）是一群离散的抗原激活淋巴母细胞，缺乏表面IgD，表达丰富的花生凝集素（PNA）细胞表面结合位点。这些表型特征使GCLC易于与几乎所有浆细胞、T细胞和未受刺激的B细胞区分开来，并使我们能够从抗原刺激的小鼠淋巴器官中识别和分离出GCLC。我们在（a）短期体内归巢研究和（b）体外检测淋巴细胞与派尔集合淋巴结和外周淋巴结冰冻切片中的毛细血管后高内皮静脉（HEV）结合的实验中，研究了这些淋巴母细胞的迁移特性。在体内实验中，与T细胞或IgD+B细胞相比，静脉注射的GCLC未能大量迁移至外周淋巴器官。在体外结合试验中，GCLC在派尔集合淋巴结或外周淋巴结切片中均不黏附于HEV。多种因素，如在肝脏中的优先滞留，可能在体内起作用影响这些细胞的定位。然而，它们几乎完全无法迁移到淋巴器官，最合理的解释是它们无法识别和黏附通常介导再循环淋巴细胞从血液迁移到这些部位的特殊HEV。使用MEL-14（一种似乎识别外周淋巴结HEV的淋巴细胞表面受体的单克隆抗体）进行的研究进一步支持了GCLC不表达功能性HEV归巢受体的概念：与大多数外周淋巴细胞不同，GCLC不结合MEL-14。当从这些细胞作为浆细胞和/或记忆B细胞前体的可能作用的角度来看时，GCLC的这些迁移和内皮识别特性使我们提出，GCLC无法识别HEV可能是暂时的，并且与静止B细胞分化阶段有关。
