Wahl R L, Wilson B S, Liebert M, Beierwaltes W H
Cancer Immunol Immunother. 1987;24(3):221-4. doi: 10.1007/BF00205633.
Nonspecific uptake of radiolabeled monoclonal antibodies in normal tissues is a significant problem for tumor imaging. A potential means of decreasing nonspecific antibody binding is to "blockade" nonspecific antibody binding sites by predosing with cold, nonspecific isotype-matched antibody, before injecting specific antibody. Nontumor-specific murine monoclonal antibody LK2H10 (IgG1) or Ab-1 (IgG2a) was given i.v. at doses of 0 to 3.5 mg to nude mice with xenografts of human melanoma. These mice were then given i.v. 4 micrograms of 131I anti-high molecular weight antigen of melanoma (HMWMAA) monoclonal antibody 763.24T (IgG1) or 225.28S (IgG2a), respectively. These mice were also given a tracer dose of 125I LK2H10 or Ab-1, respectively. Specific tumor uptake of anti-HMWMAA antibodies was see in all cases. No drop in tumor or nontumor uptake was demonstrated for either of the tumor-specific or nonspecific monoclonal antibodies due to nonspecific monoclonal antibody pretreatment. These data suggest that high doses of isotype-matched unlabeled nonspecific monoclonal antibody given before 131I tumor-specific monoclonal antibody, will not enhance tumor imaging.
放射性标记单克隆抗体在正常组织中的非特异性摄取是肿瘤成像中的一个重要问题。减少非特异性抗体结合的一种潜在方法是在注射特异性抗体之前，预先给予冷的、非特异性的同型匹配抗体，以“阻断”非特异性抗体结合位点。将非肿瘤特异性鼠单克隆抗体LK2H10（IgG1）或Ab-1（IgG2a）以0至3.5毫克的剂量静脉注射给有人黑色素瘤异种移植的裸鼠。然后分别给这些小鼠静脉注射4微克的131I抗黑色素瘤高分子量抗原（HMWMAA）单克隆抗体763.24T（IgG1）或225.28S（IgG2a）。这些小鼠还分别给予了示踪剂量的125I LK2H10或Ab-1。在所有情况下均可见抗HMWMAA抗体的特异性肿瘤摄取。由于非特异性单克隆抗体预处理，肿瘤特异性或非特异性单克隆抗体的肿瘤或非肿瘤摄取均未降低。这些数据表明，在131I肿瘤特异性单克隆抗体之前给予高剂量的同型匹配未标记非特异性单克隆抗体，不会增强肿瘤成像。
