首页 > 文献资料
-
Site-specific delivery of therapeutic drugs to their target cells is a major scientific challenge for the pharmaceutical sciences. It offers a number of advantages over conventional drug administration. With drug targeting, high local concentrations of the drug can be achieved, thus circumventing many unwanted side effects. Various carriers have been suggested for the delivery of drugs, including liposomes[1 - 5] and (neo ) glycoproteins[6-8]. The asialoglycoprotein receptor (ASGP-R) has frequently been utilized for targeting drugs to the parenchymal liver cell[6- 12]. Liposomes have several advantageous characteristics as drug carrier, and particularly, ligandtacked liposomes achieve a highly effective targeting[13]. Hara et al reported that asialofetuin (AF)-tacked liposomes distributed to rat hepatocytes selectively in vivo[14], and ASGP-R mediated the uptake of AF-liposomes encapsulating IFN-γ by isolated rat hepatocytes in vitro[15]. Lactosaminated human serum albumin (L-HSA) is a neoglycoprotein taking number of galactose residue as terminal sugar[6].
-
免疫毒素2E8-去甲斑蝥素的研制及其体外靶向抑制效应研究
Objective The immunotoxins generated by conjugating monoclonal antibody (mAb) and a certain toxin play an important and promising role in treating hematopoietic malignancies. However, most of the toxins used for the conjugation are toxic proteins, which are immunogenic in the patients. Norcantharidin (NCTD) is a small molecule toxin without immunogenicity, and thus has become a potential new drug for hematopoietic cancers. In this study, we prepared immunotoxin 2E8-NCTD by using the ZCH-4-2E8 cells produced in the laboratory of our hospital, and then detected its targeting effect against CD+19 lymphoid malignant Nalm-6 cells in vitro.Methods 2E8 mAb was obtained from mouse ascites and purified by gel chromatography. After its purity was checked by SDS-PAGE, immunotoxin 2E8-NCTD was generated by conjugating CD19 mAb with NCTD using activated ester method. The binding activity of the immunoconjugate to CD19 antigens on cell surface, and the expression levels of the CD19 antigens on Nalm-6 and K562 cells were determined by flow cytometry. The inhibitory effects of PBS, purified 2E8 mAb, NCTD, and immunotoxin 2E8-NCTD on the cell growth of either Nalm-6 or K562 cells were then compared.Results The purity of the 2E8 mAb was higher than 99% demonstrated by SDS-PAGE assay. 2E8 mAb was detected on the surface of 99.34% of the Nalm-6 cells, while on only 0.98% of the K562. The newly generated immunotoxin had a positive rate of 99.90% on the Nalm-6 with slightly reduced binding activity. Both 2E8-NCTD and NCTD significantly inhibited the growth of CD+19 Nalm-6 cells (P < 0. 001 ), while the purified 2E8 mAb did not show any significant influences on the growth of the same cell line ( P > 0.05 ). Meanwhile, no significant inhibitory effects on the CD-19 K562 cells were identified in the 2E8-NCTD, 2E8 mAb, or control groups, indicating a significant targeting effect of 2E8-NCTD against Nalm-6 cells.Conclusions The immunotoxin 2E8-NCTD can be synthesized by activated ester method. It has target killing effects on CD+19 Nalm-6 leukemia cells in vitro.