Sforzini S, de Totero D, Gaggero A, Ippoliti R, Glennie M J, Canevari S, Stein H, Ferrini S
Istituto Nazionale per la Ricerca sul Cancro, Centro di Biotecnologie Avanzate, Genova, Italy.
Br J Haematol. 1998 Sep;102(4):1061-8. doi: 10.1046/j.1365-2141.1998.00859.x.
CD25 and CD30 represent suitable target molecules for bispecific antibody (bimAb)-driven toxin delivery to lymphoid tumour cells. We describe two new anti-CD30/anti-saporin bimAbs (termed CD30 x sap1 and CD30 x sap2), produced by hybrid hybridomas, which react against non-cross-reactive epitopes of the saporin molecule, and compared their effect with a bimAb reacting with saporin and with CD25 (CD25 x sap1). In a protein synthesis inhibition assay these bimAbs were able to enhance saporin toxicity (IC50 = 8.5 x 10(-9) M in the absence of mAbs) with a similar activity: in the presence of 10(-9) M CD30 x sap1 bimAb the IC50 was 2.75 x 10(-11) M, whereas with CD30 x sap2 bimAb the IC50 was 6.5 x 10(-11) M and CD25 x sap1 bimAb displayed an IC50 of 3 x 10(-11) M (as saporin). The combined use of the two anti-CD30 bimAbs further increased cytotoxicity by 100-fold, resulting in an IC50 of 1.9 x 10(-13) M. A slightly less efficient improvement was obtained by combining the CD25 x sap1 bimAb with the CD30 x sap2 bimAb directed against a different toxin epitope (saporin IC50 to 7 x 10(-13) M). In contrast, no synergistic effect was observed using the combination of the anti-CD25 bimAb with the anti-CD30 bimAb reacting with the same epitope of saporin (IC50 = 4.5 x 10(-11) M). Analysis of FITC-saporin binding to L540 cells by flow cytometry demonstrated that the appropriate combinations of the two anti-CD30/anti-saporin bimAbs or of the anti-CD30/anti-saporin and anti-CD25/anti-saporin bimAbs had a cooperative effect on the binding of the ribosome-inactivating protein (RIP) to the cells, when compared with single bimAbs.
CD25和CD30是双特异性抗体（bimAb）驱动毒素递送至淋巴瘤细胞的合适靶分子。我们描述了两种由杂交杂交瘤产生的新型抗CD30/抗皂草素双特异性抗体（称为CD30 x sap1和CD30 x sap2），它们与皂草素分子的非交叉反应表位发生反应，并将它们的作用与一种与皂草素和CD25反应的双特异性抗体（CD25 x sap1）进行比较。在蛋白质合成抑制试验中，这些双特异性抗体能够增强皂草素的毒性（在无单克隆抗体时IC50 = 8.5×10⁻⁹ M），且活性相似：在存在10⁻⁹ M CD30 x sap1双特异性抗体时，IC50为2.75×10⁻¹¹ M，而使用CD30 x sap2双特异性抗体时IC50为6.5×10⁻¹¹ M，CD25 x sap1双特异性抗体的IC50为3×10⁻¹¹ M（与皂草素相同）。两种抗CD30双特异性抗体联合使用可使细胞毒性进一步增加100倍，导致IC50为1.9×10⁻¹³ M。将CD25 x sap1双特异性抗体与针对不同毒素表位的CD30 x sap2双特异性抗体联合使用，可获得稍低效率的改善（皂草素IC50降至7×10⁻¹³ M）。相比之下，使用与皂草素相同表位反应的抗CD25双特异性抗体和抗CD30双特异性抗体联合使用未观察到协同效应（IC50 = 4.5×10⁻¹¹ M）。通过流式细胞术分析FITC - 皂草素与L540细胞的结合表明，与单双特异性抗体相比，两种抗CD30/抗皂草素双特异性抗体或抗CD30/抗皂草素和抗CD25/抗皂草素双特异性抗体的适当组合对核糖体失活蛋白（RIP）与细胞的结合具有协同作用。
