White S, Taetle R, Seligman P A, Rutherford M, Trowbridge I S
Salk Institute, Department of Cancer Biology, San Diego, California 92138.
Cancer Res. 1990 Oct 1;50(19):6295-301.
Thirty-two murine monoclonal antibodies (MAbs) against the external domain of the human transferrin (Tf) receptor have been obtained using human Tf receptor glycoprotein produced in a baculovirus expression system as immunogen. The MAbs were tested separately, and in combination, for their ability to inhibit growth of CCRF-CEM leukemic T-cells in tissue culture. One MAb, D65.30, an IgG1, inhibited growth of CCRF-CEM cells as effectively as the anti-Tf receptor MAb 42/6, an IgA, previously found to have the highest antiproliferative activity in this assay. Some combinations of two or more MAbs inhibited the in vitro growth of CCRF-CEM much more effectively than single MAbs. Eleven IgG1 anti-Tf receptor MAbs, when combined individually with D65.30, increased the inhibition of CCRF-CEM growth from approximately 65% to greater than 90% in a 7-day growth assay. Similarly, many IgG MAbs in combination with 42/6 also inhibited CCRF-CEM growth by greater than 90%. The growth-inhibitory effects of certain combinations of MAbs were clearly synergistic, because either one or both MAbs tested separately were inactive. These pairs of MAbs also inhibited the growth of HL-60 and KG-1 leukemic cells by greater than 90% and partially inhibited the growth of K562 erythroleukemia and M21 melanoma cells, which are resistant to MAb 42/6. However, not all combinations of anti-Tf receptor MAbs were more effective; eight MAbs markedly antagonized the antiproliferative effects of D65.30, whereas 12 others had little or no effect. Preincubation of HL-60 cells with three different pairs of MAbs, D65.30 and A27.15, B3/25 and 42/6, and B3/25 and TR3A, inhibited subsequent colony formation by greater than 95%, demonstrating that their action is cytotoxic, not cytostatic. The antiproliferative activity of these pairs of MAbs correlates with their ability to block Tf-mediated 59Fe uptake and perturb Tf receptor expression. Treatment of nude mice bearing established s.c. CCRF-CEM tumors with a combination of MAbs D65.30 and A27.15 inhibited tumor growth and in some animals led to complete tumor regression. Each MAb administered separately was much less effective. We conclude that combinations of two or more anti-Tf receptor MAbs can interact synergistically to inhibit cell growth in vitro and tumor growth in vivo.
利用杆状病毒表达系统产生的人转铁蛋白（Tf）受体糖蛋白作为免疫原，已获得32种针对人Tf受体胞外域的鼠单克隆抗体（MAb）。分别对这些单克隆抗体及其组合进行了测试，以检测它们在组织培养中抑制CCRF-CEM白血病T细胞生长的能力。一种IgG1单克隆抗体D65.30抑制CCRF-CEM细胞生长的效果与抗Tf受体单克隆抗体42/6（一种IgA）相同，先前发现在该试验中42/6具有最高的抗增殖活性。两种或更多种单克隆抗体的某些组合比单个单克隆抗体更有效地抑制了CCRF-CEM在体外的生长。在为期7天的生长试验中，11种IgG1抗Tf受体单克隆抗体与D65.30单独组合时，将CCRF-CEM生长的抑制率从约65%提高到大于90%。同样，许多IgG单克隆抗体与42/6组合也将CCRF-CEM生长抑制了90%以上。某些单克隆抗体组合的生长抑制作用明显具有协同性，因为单独测试的一种或两种单克隆抗体均无活性。这些单克隆抗体对也将HL-60和KG-1白血病细胞的生长抑制了90%以上，并部分抑制了对单克隆抗体42/6耐药的K562红白血病细胞和M21黑色素瘤细胞的生长。然而，并非所有抗Tf受体单克隆抗体的组合都更有效；8种单克隆抗体显著拮抗D65.30的抗增殖作用，而另外12种则几乎没有作用或没有作用。用三种不同的单克隆抗体对（D65.30和A27.15、B3/25和42/6以及B3/25和TR3A）对HL-60细胞进行预孵育，可使随后的集落形成抑制率大于95%，表明它们的作用是细胞毒性的，而非细胞抑制性的。这些单克隆抗体对的抗增殖活性与其阻断Tf介导的59Fe摄取和扰乱Tf受体表达的能力相关。用单克隆抗体D65.30和A27.15的组合治疗已建立皮下CCRF-CEM肿瘤的裸鼠，可抑制肿瘤生长，在某些动物中导致肿瘤完全消退。单独给予每种单克隆抗体的效果要差得多。我们得出结论，两种或更多种抗Tf受体单克隆抗体的组合可协同相互作用，以抑制体外细胞生长和体内肿瘤生长。
