Enhanced catabolism of low density lipoproteins in rat by lactosaminated Fab fragment. A new carrier of macromolecules to the liver. Academic Article uri icon

Overview

abstract

  • Proteins conjugated with lactose residues exhibit enhanced hepatic uptake mediated by the galactose receptor. In this study, we demonstrate that lactosaminated Fab fragments (lac-Fab) of IgG can induce hepatic catabolism of specific antigens, especially low density lipoproteins (LDL). lac-Fab and human LDL-lac-Fab complex exhibited specific uptake in isolated rat hepatocytes. In vivo in the rat, lactosamination enhanced plasma clearance of Fab fragments 2-fold and hepatic localization 20-fold. Fab fragments retained their affinity after lactosamination. Hepatic uptake of rat 125I-IgG complexed in vitro with anti-rat lac-Fab was increased almost 5-fold, compared to rat 125I-IgG alone. Injection of rats with anti-LDL lac-Fab induced plasma clearance and hepatic uptake of tracer amounts of previously injected human 125I-LDL, which decreased 50% 10 min after injection of lac-Fab, with 30% present in the liver. Asialofetuin completely inhibited these processes. After a bolus of 6 mg of human LDL, administration of anti-LDL lac-Fab reduced the serum cholesterol of rats to basal values within 2.5 h. These findings suggest that lactosaminated Fab fragments of specific IgGs are effective reagents for inducing hepatic uptake of macromolecules through the galactose receptor. lac-Fab specific for LDL may be an effective hypocholesterolemic agent in vivo.

publication date

  • July 15, 1986

Research

keywords

  • Immunoglobulin Fab Fragments
  • Immunoglobulin G
  • Lactose
  • Lipoproteins, LDL
  • Liver

Identity

Scopus Document Identifier

  • 0022980404

PubMed ID

  • 3013882

Additional Document Info

volume

  • 261

issue

  • 20