title: Preparation and in vitro targeting of sterically stabilized liposomes modified with chimeric TNT-3 monoclonal antibody.
abstract: OBJECTIVE
  To prepare sterically stabilized liposomes modified with chimeric TNT-3 monoclonal antibody (chTNT-3) and investigate their immunoreactivity and in vitro targeting.
  
  
  METHODS
  An end-group functionalized polyethylene glycol-lipid derivative (pyridylthiopropionoylamino-polyethylene glycol-hydrogenated soy phosphatidylethanolamine, PDP-PEG-HSPE) was synthesized and incorporated to sterically stabilized liposomes. After mild thiolysis of the PDP groups by dithiothreitol, liposomes were covalently linked with maleimide-derivatized chTNT-3 and formed sterically stabilized immunoliposomes. Coupling efficiency, antibody density, size distribution, immunoreactivity of chTNT-3-modified sterically stabilized liposomes (chTNT-3-SLs) and specific binding properties of the chTNT-3-SLs to fixed Raji cells were determined, separately.
  
  
  RESULTS
  Higher initial Ab/PDP-PEG-HSPE molar ratios resulted in higher antibody density on the surface of liposomes but lower coupling efficiency. The optimal coupling efficiency of 71% was obtained while antibody density in liposome was 106 microg antibody/micromol phospholipids (as initial antibody/PDP-PEG-HSPE = 1 : 10). The chTNT-3-SLs had a narrow size distribution after extrusion and the mean size of this immunoliposomes was (115 +/- 33) nm. The immunoreactivity of chTNT-3 can be preserved after efficient attachment of maleimide-derivatized chTNT-3 to the surface of liposomes. But calculated per antibody concentration, the immunoreactivity of chTNT-3-SLs would obviously decrease compared to that of chTNT-3 or chTNT-3 derivatives. Significantly higher binding of chTNT-3-SLs to fixed Raji cells directed by chTNT-3 was obtained compared to other preparations in serial dilutions (P < 0.01).
  
  
  CONCLUSIONS
  chTNT-3-SLs prepared by PDP-PEG-HSPE method remained most immunoreactivity of chTNT-3 and was able to bind nuclear antigens in vitro.
authors.affiliation: Fudan-Pharmco Targeting Drug Research Center, School of Pharmacy, Fudan University, Shanghai 200032, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Pan
authors.forename: Guo-Qin
authors.initials: GQ
authors.lastname: Niu
authors.forename: Jun
authors.initials: J
authors.lastname: Pan
authors.forename: Wei-Yue
authors.initials: WY
authors.lastname: Lu
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology*; D001665:Binding Sites; D045744:Cell Line, Tumor; D004337:Drug Carriers; D016503:Drug Delivery Systems; D006801:Humans; D008081:Liposomes; D016393:Lymphoma, B-Cell / Q000276:immunology* / Q000473:pathology; D009336:Necrosis; D010714:Phosphatidylethanolamines; D011092:Polyethylene Glycols
chemical_list: D000911:Antibodies, Monoclonal; D004337:Drug Carriers; D008081:Liposomes; D010714:Phosphatidylethanolamines; D011092:Polyethylene Glycols