Behr T M, Sharkey R M, Juweid M E, Blumenthal R D, Dunn R M, Griffiths G L, Bair H J, Wolf F G, Becker W S, Goldenberg D M
Garden State Cancer Center, Center for Molecular Medicine and Immunology, Newark, New Jersey 07103-2763, USA.
Cancer Res. 1995 Sep 1;55(17):3825-34.
The renal uptake of radiolabeled antibody fragments and peptides is a problem in radioimmunodetection and radioimmunotherapy, especially with intracellular retained radiometals. The aim of this study was to develop suitable methods to reduce this kidney uptake. BALB/c mice or nude mice bearing the human GW-39 colon carcinoma xenograft were given i.p. injections of basic amino acids or a range of different basic amino acid derivatives, amino sugars, as well as cationic peptides. The effect of these agents on the biodistribution of Fab' and F(ab')2 fragments of different mAbs radiolabeled with 99mTc, 188Re, 111In, 88Y, or 125I was studied. Tumor and organ uptake was determined and compared to untreated mice. The kidney uptake of Fab' fragments was reduced 5-6-fold in a dose-dependent manner as compared to untreated controls. The uptake in all other organs, as well as the tumor, was unaffected. A similar reduction in renal retention was seen for all other intracellularly retained isotopes, as well as for F(ab')2 fragments. D- and L-isomers of lysine were equally effective whether given i.p. or p.o. D-glucosamine was effective, but its N-acetyl derivative was not. Basic polypeptides (e.g., poly-L-lysine) were also effective; their potency increased with increasing molecular weight. HPLC of the urine taken from treated animals showed the excretion of intact Fab', in contrast to mostly low-molecular-weight metabolites in the control group. These studies indicate that a variety of basic compounds is capable of inhibiting the tubular reabsorption of peptides and proteins, thus lowering the kidney uptake of antibody fragments significantly. On a molecular basis, the effect seems to essentially rely on the presence of a positively charged amino group. By reducing renal retention of antibody fragments, their role as imaging and therapeutic agents may be expanded.
在放射免疫检测和放射免疫治疗中，尤其是对于细胞内保留放射性金属的情况，放射性标记抗体片段和肽的肾脏摄取是一个问题。本研究的目的是开发合适的方法来减少这种肾脏摄取。给携带人GW-39结肠癌异种移植瘤的BALB/c小鼠或裸鼠腹腔注射碱性氨基酸或一系列不同的碱性氨基酸衍生物、氨基糖以及阳离子肽。研究了这些试剂对用99mTc、188Re、111In、88Y或125I标记的不同单克隆抗体的Fab'和F(ab')2片段生物分布的影响。测定肿瘤和器官摄取并与未处理小鼠进行比较。与未处理的对照组相比，Fab'片段的肾脏摄取以剂量依赖方式降低了5至6倍。所有其他器官以及肿瘤的摄取均未受影响。对于所有其他细胞内保留的同位素以及F(ab')2片段，肾脏潴留也有类似程度的降低。赖氨酸的D-和L-异构体无论是腹腔注射还是口服给药都同样有效。D-葡萄糖胺有效，但其N-乙酰衍生物无效。碱性多肽（例如聚-L-赖氨酸）也有效；其效力随分子量增加而增强。对处理动物尿液的HPLC分析显示有完整的Fab'排出，而对照组中大多是低分子量代谢物。这些研究表明，多种碱性化合物能够抑制肽和蛋白质的肾小管重吸收，从而显著降低抗体片段的肾脏摄取。从分子层面来看，这种作用似乎主要依赖于带正电荷氨基的存在。通过减少抗体片段的肾脏潴留，它们作为成像和治疗剂的作用可能会得到扩展。
