Study of Coxsackie B viruses interactions with Coxsackie Adenovirus receptor and Decay-Accelerating Factor using Human CaCo-2 cell line.

Samira Riabi,Sylvie Pillet,Rafik Harrath,Bruno Pozzetto,Imed Gaaloul,Dorsaf Nasri,Mahjoub Aouni,Lamjed Bouslama

doi:10.1186/1423-0127-21-50

Abstract

BackgroundDecay Accelerating Factor (DAF) and Coxsackievirus-Adenovirus Receptor (CAR) have been identified as cellular receptors for Coxsackie B viruses (CV-B). The aim of this study is to elucidate the different binding properties of CV-B serotypes and to find out if there are any amino acid changes that could be associated to the different phenotypes.Twenty clinical CV-B isolates were tested on CaCo-2 cell line using anti-DAF (BRIC216) and anti-CAR (RmcB) antibodies. CV-B3 Nancy prototype strain and a recombinant strain (Rec, CV-B3/B4) were tested in parallel. The P1 genomic region of 12 CV-B isolates from different serotypes was sequenced and the Trans-Epithelial Electrical Resistance (TEER) along with the virus growth cycle was measured.ResultsInfectivity assays revealed clear differences between CV-B isolates with regard to their interactions with DAF and CAR. All tested CV-B isolates showed an absolute requirement for CAR but varied in their binding to DAF. We also reported that for some isolates of CV-B, DAF attachment was not adapted. Genetic analysis of the P1 region detected multiple differences in the deduced amino acid sequences.ConclusionWithin a given serotype, variations exist in the capacity of virus isolates to bind to specific receptors, and variants with different additional ligands may arise during infection in humans as well as in tissue culture.

Highlights

Decay Accelerating Factor (DAF) and Coxsackievirus-Adenovirus Receptor (CAR) have been identified as cellular receptors for Coxsackie B viruses (CV-B)
Trans-Epithelial Electrical Resistance (TEER) measurement Polarized monolayers of CaCo-2 cells were cultured in transwell filters until TEER measurement was stable (300 to 350 Ω.cm2 in 12 to 14 days) (Figure 1)
When the cells were exposed to virus isolates, a drop in TEER (Figure 2) was evident within 30 min pi for CV-B1, 3 and 5 serotypes

Summary

Introduction

Decay Accelerating Factor (DAF) and Coxsackievirus-Adenovirus Receptor (CAR) have been identified as cellular receptors for Coxsackie B viruses (CV-B). CAR is a 46 kDa membrane glycoprotein and part of a larger protein complex in the tight junction of the cell and might function as a cell–cell adhesion molecule [10,11,12]. DAF functional region consists of four short consensus repeats (SCR1 to 4) [16,17,19] This protein was described as a receptor for echoviruses, Enterovirus 70, and Coxsackievirus A 21 [20,21,22]. Even CV-B strains with strong DAF-binding properties require the CAR protein to mediate lytic infection [23,24,25,26]. Most cell-associated viruses are converted into an irreversibly altered form, the A particle, which has lost the internal capsid protein VP4, and no longer interacts with cellular receptors or infects receptor-bearing cells [28]

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