ABSTRACT
Immunoassay relies on antibodies, but traditional antibodies such as monoclonal antibody (mAb) require animal immunization and complex procedures. Single-chain variable fragment (scFv) becomes a potential alternative to mAb with advantages of the low cost, rapid and easy prepared. In the present study, we prepared scFvs against dihydroartemisinin (DHA) based on E. coli and HEK293T cell expression system, named MBP-scFv and scFv-Fc, respectively. Their properties were compared with the parent mAb. The calculated affinity constants of mAb, MBP-scFv and scFv-Fc were 2.1 × 108 L mol-1, 2.2 × 107 L mol-1 and 1.6 × 108 L mol-1, respectively. The half inhibitory concentration (IC50) of mAb, MBP-scFv and scFv-Fc were 1.16 ng mL-1, 2.15 ng mL-1 and 6.57 ng mL-1, respectively. Both the scFv showed less sensitive than the mAb based on the IC50. The cross-reactivities of MBP-scFv for artemisinin and artesunate exhibited similarities to the mAb, yet the cross-reactivities of scFv-Fc for these compounds exceeded those of the mAb significantly. The stability of the scFvs was ascertained to be maintained for over 5 days at room temperature, and for more than a month at both 4 °C and - 20 °C. After that, the indirect competitive enzyme-linked immunosorbent assays (icELISAs) based on the scFv from E. coli were used to detect the DHA content in eight drug samples, and the result was consistent with ultra-performance liquid chromatography simultaneously. Although scFv can be used for quantitative determination of drugs, but it still cannot completely replace mAb in immunoassay without evolution and modification.
ABSTRACT
Background & Aims: We compared the efficacy of transcatheter arterial chemoembolization (TACE) in combination with CT-guided radiofrequency ablation (RFA) with that of surgical resection (SR) in patients with hepatocellular carcinoma (HCC) within the up-to-seven criteria. Methods: From January 2004 to December 2014, 420 multicenter consecutive patients with HCC who conformed to the up-to-seven criteria and initially received either TACE plus CT-guided RFA (TACE-RFA) or SR were enrolled. A matched cohort composed of 206 patients was selected after adjustment with propensity score matching. The overall survival (OS) of each patient was calculated with the Kaplan-Meier method and compared by the log-rank test. Results: The median OS and 1-, 3-, and 5-year survival rates were 56.0 months, 96.1%, 76.7% and 41.3% in the TACE-RFA group and 58.0 months, 96.1%, 86.4% and 46.2% in the SR group, respectively. There was no significant difference in OS between the two groups (P = 0.138). For patients with HCC beyond the Milan criteria, TACE-RFA provided a longer median OS than SR (52.0 vs 45.0 months, P = 0.023). Conclusions: Treatment by TACE-RFA conferred an OS rate comparable with that of SR in patients within the up-to-seven criteria. For patients with HCC between the Milan and the up-to-seven criteria, TACE-RFA might be superior to SR for survival prolongation.
