Original Article
Copyright ©2010 Baishideng. All rights reserved.
World J Hepatol. Feb 27, 2010; 2(2): 74-80
Published online Feb 27, 2010. doi: 10.4254/wjh.v2.i2.74
ApoB-containing lipoproteins promote infectivity of chlamydial species in human hepatoma cell line
Yuriy K Bashmakov, Nailia A Zigangirova, Alexander L Gintzburg, Petr A Bortsov, Ivan M Petyaev
Yuriy K Bashmakov, Ivan M Petyaev, Cambridge Theranostics Ltd, Babraham Research Campus, Babraham, Cambridge, CB2 4AT, United Kingdom
Nailia A Zigangirova, Alexander L Gintzburg, Petr A Bortsov, Gamaleya Institute for Epidemiology and Microbiology RAMS, 18 Gamaleya Str., Moscow 123098, Russia
Author contributions: Bashmakov YK and Zigangirova NA performed most of the experiments; Bortsov PA did flow cytometry analysis and immunostaining; Gintzburg AL and Petyaev IM were involved in study initiation, writing the manuscript and providing financial support.
Supported by Cambridge Theranostics Ltd
Correspondence to: Dr. Yuriy K Bashmakov, MD, PhD, Cambridge Theranostics Ltd, Babraham Research Campus, Cambridge, CB2 4AT, United Kingdom. yuriy@cammedica.com
Telephone: +44-797-1598348 Fax: +44-122-3240340
Received: August 14, 2009
Revised: January 4, 2010
Accepted: January 11, 2010
Published online: February 27, 2010

AIM: To evaluate the direct binding of two main chlamydial biovars (C. trachomatis and C. pneumoniae) to plasma lipoproteins and its effect on chlamydial infection rate in human hepatoma cell line (HepG2 cells).

METHODS: Murine plasma lipoproteins were fractionated and isolated using fast-performance liquid chromatography (FPLC), spotted on nitrocellulose membrane and incubated with chlamydial suspensions. Direct binding of chlamydial particles to lipoprotein fractions has been studied using lipopolysaccharide-specific antibodies in immuno-dot blot binding assay and immunoprecipitation analysis. Immunostaining protocol as well as flow cytometry analysis have been employed to study the infectivity rate of chlamydial species in HepG2 cells.

RESULTS: Elementary bodies of both C. trachomatis and C. pneumoniae bind ApoB-containing fractions of plasma lipoproteins. That binding becomes stronger when heat-denatured FPLC fractions are used, suggesting a primary role of apolipoproteins in interaction between chlamydial particle and lipoprotein. Both chlamydial biovars efficiently propagate in human hepatoma cell line - HepG2 cells even in serum free conditions forming late-stage inclusion bodies and releasing extracellular elementary bodies. Preincubation of C. trachomatis and C. pneumoniae with native ApoB-containing lipoproteins enhances the rate of chlamydial infection in HepG2 cells.

CONCLUSION: A productive infection caused by C. trachomatis and C. pneumoniae may take place in human-derived hepatocytes revealing hepatic cells as possible target in chlamydial infection. Obtained results may suggest the participation of lipoprotein receptors in the mechanism of attachment and/or entry of chlamydial particles into target cells.

Keywords: ApoB-containing lipoproteins, Chlamydial trachomatis, Chlamydial pneumoniae, Human hepatoma cell line, Liver infection