RESEARCH ARTICLE SPECT Imaging with 99m Tc-Labeled EGFR-Specific Nanobody for In Vivo Monitoring of EGFR Expression

摘要: Purpose: Overexpression of the epidermal growth factor receptor (EGFR) occurs with high incidence in various carcinomas. The oncogenic expression has been exploited for immunoglobulin-based diagnostics and therapeutics. We describe use a llama singledomain antibody fragment, termed Nanobody ® , vivo radioimmunodetection EGFR overexpressing tumors using single photon emission computed tomography (SPECT) mice. Methods: Fluorescence-activated cell sorting (FACS) analysis was performed to evaluate specificity selectivity 8B6 bind on cells. then labeled 99m Tc via its C-terminal histidine tail. Uptake normal organs tissues assessed by ex analysis. In tumor targeting Tc-8B6 evaluated pinhole SPECT mice bearing xenografts cells either (A431) or moderate (DU145) overexpression EGFR. Results: FACS indicated that only recognizes blood clearance is relatively fast (half-life, 1.5 h) mainly kidneys. At 3 h postinjection, total kidney accumulation (46.6±0.9%IA) compared liver uptake (18.9±0.6%IA). Pinhole imaging A431 showed higher average (5.2±0.5%IA/cm )o f DU145 (1.8±0.3%IA/cm pG0.001). Conclusion: EGFR-binding investigated this study shows towards enabled discrimination between overexpression. favorable biodistribution further corroborates suitability Nanobodies imaging.