Sforzini S, Bolognesi A, Meazza R, Marciano S, Casalini P, Dürkop H, Tazzari P L, Stein H, Stirpe F, Ferrini S
Istituto Nazionale per la Ricerca sul Cancro, Genova, Italy.
Br J Haematol. 1995 Jul;90(3):572-7. doi: 10.1111/j.1365-2141.1995.tb05586.x.
Lymphocyte activation antigens, such as CD30, represent suitable target molecules for antibody-driven drug delivery in haemopoietic malignancies. A ribosome-inactivating protein (RIP) type 1 of potential interest for mAb targeting is gelonin, which displays a lower toxicity, as compared to other RIPs. In this study, two anti-CD30/antigelonin bispecific monoclonal antibodies (bimAbs), secreted by hybrid hybridomas, were used to deliver this RIP to CD30+ tumour cells. The two bimAbs, termed D4 and A18, were produced using the same anti-CD30 mAb and two anti-gelonin mAbs, directed to unrelated epitopes of the gelonin molecule. These bimAbs enhanced gelonin toxicity (IC50 5 x 10(-8) M, in the absence of mAbs) against the CD30+ L540 Hodgkin's lymphoma cell line in a protein synthesis inhibition assay. Thus, in the presence of 10(-9) M D4 bimAb, protein synthesis was inhibited with an IC50 of 5 x 10(-10) M as gelonin, whereas with A18 bimAb the IC50 was 8 x 10(-11) M. More interestingly, the combined use of the two bimAbs had a synergistic effect, since the IC50 of gelonin reached 6 x 10(-12) M. Among CD30 tumour cell lines, the Hodgkin's lymphoma L428 was also sensitive to gelonin delivered by bimAbs (IC50 6 x 10(-11) M), whereas the COLE Hodgkin's cell line and the T-ALL Jurkat were completely resistant to the toxic effect of gelonin and bimAbs. COLE and Jurkat cells were also resistant to a gelonin/anti-CD30 conventional immunotoxin, whereas they were sensitive to a saporin/anti-CD30 immunotoxin. This suggests that the resistance to gelonin is not related to a lack of internalization through the CD30 molecule but is associated with some property of the RIP.
淋巴细胞激活抗原，如CD30，是血液系统恶性肿瘤中抗体驱动药物递送的合适靶分子。对于单克隆抗体靶向而言，一种潜在有价值的1型核糖体失活蛋白（RIP）是相思豆毒蛋白，与其他RIP相比，它的毒性较低。在本研究中，利用杂交杂交瘤分泌的两种抗CD30/抗相思豆毒蛋白双特异性单克隆抗体（双特异性抗体）将这种RIP递送至CD30+肿瘤细胞。这两种双特异性抗体，称为D4和A18，是使用相同的抗CD30单克隆抗体和两种抗相思豆毒蛋白单克隆抗体制备的，它们针对相思豆毒蛋白分子的不相关表位。在蛋白质合成抑制试验中，这些双特异性抗体增强了相思豆毒蛋白对CD30+L540霍奇金淋巴瘤细胞系的毒性（在无单克隆抗体时IC50为5×10⁻⁸M）。因此，在存在10⁻⁹M D4双特异性抗体的情况下，蛋白质合成被抑制，IC50为5×10⁻¹⁰M（与相思豆毒蛋白相同），而使用A18双特异性抗体时IC50为8×10⁻¹¹M。更有趣的是，两种双特异性抗体联合使用具有协同作用，因为相思豆毒蛋白的IC50达到6×10⁻¹²M。在CD30肿瘤细胞系中，霍奇金淋巴瘤L428对双特异性抗体递送的相思豆毒蛋白也敏感（IC50为6×10⁻¹¹M），而COLE霍奇金细胞系和T-ALL Jurkat细胞对相思豆毒蛋白和双特异性抗体的毒性完全耐药。COLE和Jurkat细胞对相思豆毒蛋白/抗CD30传统免疫毒素也耐药，而它们对皂草素/抗CD30免疫毒素敏感。这表明对相思豆毒蛋白的耐药性与通过CD30分子内化不足无关，而是与RIP的某些特性有关。
