Corcione A, Baldi L, Zupo S, Dono M, Rinaldi G B, Roncella S, Taborelli G, Truini M, Ferrarini M, Pistoia V
Laboratory of Oncology, Giannina Gaslini Scientific Institute, Genoa, Italy.
J Immunol. 1994 Oct 1;153(7):2868-77.
The ability of human B lymphocytes to produce granulocyte (G)-CSF in vitro was investigated. Highly purified tonsillar B cells were fractionated into large and small cells by a Percoll density gradient, cultured, and tested for G-CSF gene expression. Large B cells spontaneous produced G-CSF mRNA and protein, whereas small B cells did not, even after incubation with various stimuli. Immunophenotypic analyses showed that large B lymphocytes contained approximately 60 to 70% of cells with the characteristic surface markers of germinal center (GC) B cells (CD38+, CD10+, and surface IgG+). The remaining cells expressed CD39, CD23, and surface IgD and were presumably in vivo-activated follicular mantle zone B cells. Fractionation of the large B lymphocytes into CD39+, surface IgD+, and CD39-, surface IgD- cells showed that the latter, but not the former, cell type produced G-CSF spontaneously in culture. Stimulation of purified (CD39-, surface IgD-) GC B cells with a CD40 mAb alone or in combination with IL-4 increased G-CSF production. Because these stimuli rescued a large fraction of GC cells (up to 50%) from spontaneous apoptosis in vitro, the finding may suggest that prevention of apoptotic death resulted in an increased G-CSF production or that CD40 mab and/or IL-4 increased G-CSF gene expression in G-CSF-producing GC B cells. Malignant B cells purified from the invaded lymph nodes of three patients with follicular center cell lymphoma and three Burkitt lymphoma cell lines, which had an immunophenotype identical with that of normal GC B cells, spontaneously produced G-CSF in vitro, thus confirming the GC origin of the cytokine. Incubation of normal purified GC B cells with rG-CSF resulted in the rescue of GC B cells from apoptosis, suggesting that G-CSF may be used by GC B cells in an autocrine manner. This autocrine loop of production and response to G-CSF by GC B cells may be activated by stimuli such as those delivered via the surface CD40 molecule, that participate in the rescue of GC B cells from apoptosis.
研究了人B淋巴细胞在体外产生粒细胞集落刺激因子（G-CSF）的能力。通过Percoll密度梯度将高度纯化的扁桃体B细胞分为大细胞和小细胞，进行培养并检测G-CSF基因表达。大B细胞可自发产生G-CSF mRNA和蛋白质，而小B细胞即使在与各种刺激物孵育后也不产生。免疫表型分析显示，大B淋巴细胞中约60%至70%的细胞具有生发中心（GC）B细胞的特征性表面标志物（CD38+、CD10+和表面IgG+）。其余细胞表达CD39、CD23和表面IgD，推测为体内活化的滤泡套区B细胞。将大B淋巴细胞分为CD39+、表面IgD+细胞和CD39-、表面IgD-细胞，结果显示，后一种细胞类型而非前一种细胞类型在培养中可自发产生G-CSF。单独用CD40单克隆抗体或与IL-4联合刺激纯化的（CD39-、表面IgD-）GC B细胞可增加G-CSF的产生。由于这些刺激物在体外可使大部分GC细胞（高达50%）免于自发凋亡，这一发现可能表明，防止凋亡死亡可导致G-CSF产生增加，或者CD40单克隆抗体和/或IL-4可增加产生G-CSF的GC B细胞中的G-CSF基因表达。从3例滤泡中心细胞淋巴瘤患者的侵袭性淋巴结中纯化的恶性B细胞以及3种伯基特淋巴瘤细胞系，其免疫表型与正常GC B细胞相同，在体外可自发产生G-CSF，从而证实了该细胞因子的GC来源。用重组G-CSF孵育正常纯化的GC B细胞可使GC B细胞免于凋亡，这表明G-CSF可能被GC B细胞以自分泌方式利用。GC B细胞产生和对G-CSF作出反应的这种自分泌环路可能被诸如通过表面CD40分子传递的刺激物激活，这些刺激物参与使GC B细胞免于凋亡。
