Romagnani S, Giudizi G M, Maggi E, Almerigogna F, Biagiotti R, Del Prete G, Mazzetti M, Alessi A, Vercelli D, Ricci M
Eur J Immunol. 1985 Dec;15(12):1158-64. doi: 10.1002/eji.1830151203.
The activity of purified interleukin 2 (IL2), obtained by the recombinant DNA technology, on the proliferative response of human B cells stimulated with low concentrations of anti-mu antibody was investigated. Recombinant IL2 was capable of augmenting the proliferative response of anti-mu-activated B cells and the T cell activation (Tac) antigen was expressed on a substantial proportion of normal B cells stimulated with anti-mu antibody. However, crude supernatants from protein A-stimulated peripheral blood mononuclear cells, which were found to possess both IL2 and B cell growth factor (BCGF) activities, maintained the ability to promote proliferation of anti-mu-activated B cells after depletion of IL2. In addition, supernatants from some T cell clones, apparently free of IL2 activity, displayed strong BCGF activity in the co-stimulation assay with anti-mu antibody. This BCGF activity was found in 25 kDa fractions by gel filtration and it was unaffected by addition to the cultures of anti-Tac antibody, which consistently inhibited the B cell proliferative response promoted by recombinant IL2. The proliferative response of anti-mu-activated B cells to clonal, IL2-free supernatants containing BCGF and recombinant IL2 present together from the beginning of culture was close to the sum of responses to the two stimulants, separately. In addition, the presence of clonal supernatant containing BCGF from the beginning of culture had a synergistic effect in the response of activated B cells to the subsequent addition of IL2, whereas the initial presence of IL2 had no such an effect on the reactivity of anti-mu-stimulated B cells to the late addition of clonal supernatant containing BCGF. The synergistic effect of BCGF in the IL2-promoted B cell proliferation was probably the result of the recruitment of a greater number of IL2-reactive B cells. In fact, the number of Tac-positive cells was significantly higher in 36-h cultures established in the presence of anti-mu antibody plus clonal supernatant containing BCGF than in cultures stimulated with anti-mu antibody alone. Taken together, these data indicate that anti-mu antibody promotes the expression by normal human B cells of distinct receptors for IL2 and a BCGF distinct from IL2. They also suggest that BCGF can exert a synergistic effect in the IL2-promoted proliferation of activated B cells.
研究了通过重组DNA技术获得的纯化白细胞介素2（IL2）对低浓度抗μ抗体刺激的人B细胞增殖反应的活性。重组IL2能够增强抗μ激活的B细胞的增殖反应，并且T细胞活化（Tac）抗原在相当比例的抗μ抗体刺激的正常B细胞上表达。然而，来自蛋白A刺激的外周血单核细胞的粗上清液，被发现同时具有IL2和B细胞生长因子（BCGF）活性，在去除IL2后仍保持促进抗μ激活的B细胞增殖的能力。此外，一些明显无IL2活性的T细胞克隆的上清液，在与抗μ抗体的共刺激试验中显示出强大的BCGF活性。通过凝胶过滤在25 kDa组分中发现了这种BCGF活性，并且它不受抗Tac抗体添加到培养物中的影响，抗Tac抗体始终抑制重组IL2促进的B细胞增殖反应。从培养开始就同时存在含有BCGF的克隆性、无IL2的上清液和重组IL2时，抗μ激活的B细胞对其的增殖反应接近分别对这两种刺激物反应的总和。此外，从培养开始就存在含有BCGF的克隆性上清液，在活化B细胞对随后添加的IL2的反应中具有协同作用，而最初存在IL2对抗μ刺激的B细胞对后期添加的含有BCGF的克隆性上清液的反应性没有这种作用。BCGF在IL2促进的B细胞增殖中的协同作用可能是招募了更多IL2反应性B细胞的结果。事实上，在存在抗μ抗体加含有BCGF的克隆性上清液的情况下建立的36小时培养物中，Tac阳性细胞的数量明显高于仅用抗μ抗体刺激的培养物。综上所述，这些数据表明抗μ抗体促进正常人B细胞表达不同的IL2受体和一种不同于IL2的BCGF。它们还表明BCGF可以在IL2促进的活化B细胞增殖中发挥协同作用。
