Establishment of an In Vitro Model of Persistent Chicken Anemia Virus Infection.

Hieu Van Dong,Dai Quang Trinh,Giang Thi Huong Tran,Kunitoshi Imai,Yohei Takeda,Haruko Ogawa

doi:10.3390/pathogens9100842

Abstract

Persistent infection of chicken anemia virus (CAV) in chickens has been suspected to result in immunosuppression and exogenous virus contamination within vaccine production. However, no direct evidence for persistent CAV infection has thus far been obtained. In this study, we aimed to establish an in vitro model of persistent CAV infection. CAV-infected MDCC-MSB1 (MSB1) cells, a Marek’s disease virus-transformed continuous cell line, were cultured in the presence of both CAV and CAV neutralizing antibody (NA). Cell viability, expression of viral antigens, viral DNA, and recovery of CAV were examined by acridine orange/propidium iodide staining, immunofluorescence measurement, real-time PCR, and viral isolation, respectively. The results indicated that CAV was maintained and possibly replicated in CAV-infected cells cultured in the presence of NA, without affecting host cell viability. It was also shown that persistently infectious CAV induced cell death again after removing NA. The persistent infection of CAV in MSB1 cells was not related to viral gene mutation. In summary, we have herein established a novel model of persistent CAV infection in MSB1 cells cultured in the presence of NA.

Highlights

Chicken anemia virus (CAV), a member of the genus Gyrovirus in the family Anelloviridae, is characterized as a non-enveloped, spherical small virus [1]
chicken anemia virus (CAV) infection did result in cell death, which was suppressed in the presence of neutralizing antibody (NA)
In order to demonstrate whether non-neutralizing antibody affects CAV-infected cells or not, an additional study on CAV-infected cells cultured in the presence of SPF chicken serum (i.e., CAV-infected + SPFs) was performed in the passage study

Summary

Introduction

Chicken anemia virus (CAV), a member of the genus Gyrovirus in the family Anelloviridae, is characterized as a non-enveloped, spherical small virus [1]. The viral genome consists of circular, negative-sense single-stranded DNA with three open reading frames (ORFs)—1, 2, and 3. These ORFs encode three viral proteins (VPs), the major capsid structural protein VP1, scaffolding VP2, and strong inducer of apoptosis VP3 (apoptin), respectively [1,2]. The VP1 protein is known to induce the production of neutralizing antibody (NA) in the host and is produced within the early phase of infection at 12 h post-infection (hpi) in Marek’s disease virus-transformed continuous cell line. Apoptin contributes to the induction of apoptosis both in vitro and in vivo [4,5]. The interaction between VP2 and apoptin influences the downregulation of apoptosis in vitro [6]

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