Binding of C3 and C3dg to the CR2 complement receptor induces growth of an Epstein-Barr virus-positive human B cell line.
Binding of C3 and C3dg to the CR2 complement receptor induces growth of an Epstein-Barr virus-positive human B cell line.
复制标题
C3 和 C3dg 与 CR2 补体受体的结合诱导 Epstein-Barr 病毒阳性人 B 细胞系的生长。
作者：
A. Hatzfeld;E. Fischer;J. Lévesque;R. Perrin;J. Hatzfeld;M. Kazatchkine
通过在只添加转铁蛋白的无血清培养基中以低密度（1至1.5 × 10(3)个细胞/ml）进行细胞培养，研究了配体与C3d/C3dg补体受体（CR2）相互作用对人B淋巴母细胞样细胞增殖的影响。这种培养基不允许Raji细胞增殖，在48小时内死亡并形成多核细胞。将纯化的人C3添加到培养物中导致细胞的剂量依赖性增殖。在含有10微克/毫升C3的培养基中，Raji细胞稳定生长，倍增时间为36小时。在等摩尔浓度的纯化C3dg中发现了与天然C3存在时相似的生长速率，而在C3c中则没有。F（ab’）2抗c3d抗体抑制C3的有丝分裂作用，而F（ab’）2抗c3c抗体不抑制。直接抑制C3dg与CR2结合的单克隆抗体OKB7预孵育Raji细胞，完全抑制c3诱导的细胞生长。C3对不表达CR2的T淋巴瘤源性细胞系JM和单核细胞系U937的生长没有促进作用。这些结果提供了CR2和C3片段之间的相互作用刺激B系人类细胞增殖的直接证据。由于CR2也作为eb病毒在B细胞上的受体，我们的结果可能与病毒的B细胞有丝分裂特性有关。
The effect of ligand interactions with the C3d/C3dg complement receptor (CR2) on proliferation of human B lymphoblastoid cells was investigated by using cell cultures performed at low density (1 to 1.5 x 10(3) cells/ml) in a serum-free defined medium to which only transferrin had been added. This medium does not allow proliferation of Raji cells which die within 48 hr with formation of polykaryons. Addition of purified human C3 to the cultures resulted in a dose-dependent proliferation of the cells. A steady growth of Raji cells with a doubling time of 36 hr was observed in cultures containing 10 micrograms/ml of C3. A growth rate similar to that observed in the presence of native C3 was found in the presence of equimolar concentrations of purified C3dg but not of C3c. F(ab')2 anti-C3d but not F(ab')2 anti-C3c antibodies inhibited the mitogenic effect of C3. Preincubation of Raji cells with monoclonal antibody OKB7 which directly inhibits the binding of C3dg to CR2, totally suppressed C3-induced growth of the cells. C3 did not enhance growth of the T lymphoma-derived cell line JM and monocytic cell line U937 which do not express CR2. These results provide direct evidence that the interaction between CR2 and C3 fragments stimulates proliferation of human cells of the B lineage. Because CR2 also acts as a receptor for Epstein-Barr virus on B cells, our results may pertain to the B cell mitogenic properties of the virus.