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Genomic variations in echovirus 30 persistent isolates recovered from a chronically infected immunodeficient child and comparison with the reference strain.

ABSTRACT: Seven sequential isolates of echovirus type 30 (EV30) were recovered over 22 months from a child with severe combined immune deficiency syndrome. The nucleotide sequences of the 5' halves of the genomes (4,400 nucleotides) of the first (S1) and last (S7) isolates were determined and compared with that of the EV30 Bastianni reference strain, also determined in this study. In genome regions P1 and P2, 101 variations were identified between the two isolates. Synonymous differences far outnumbered nonsynonymous differences. Amino acid changes affected both capsid and nonstructural polypeptides (particularly 2B). The VP1 nucleotide sequences of the seven isolates were determined to analyze genome evolution during the chronic infection. In the phylogenetic tree, the seven isolates were directly related to the prototype strain in an individual monophyletic group, strongly suggesting that the chronic infection in the child arose from a single persistent EV30 isolate. Four lineages were observed in the persistent isolates. Isolates S2, S4, S5, and S6 were close relatives of one another, whereas isolates S1 and S3 formed individual lineages. Isolate S7, distantly related to all other isolates, formed the fourth lineage. These findings suggest the quasispecies nature of the genomes of the seven sequential EV30 isolates. Grouping of persistent isolates on the basis of replicative capacities was consistent with phylogenetic relationships. Overall, the results indicate that genetically related EV30 variants with different replicative capacities coexisted in a carrier state, probably in the gastrointestinal tract, during the infection of the child.

SUBMITTER: Bailly JL

PROVIDER: S-EPMC86147 | biostudies-literature | 2000 Feb

REPOSITORIES: biostudies-literature

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Genomic variations in echovirus 30 persistent isolates recovered from a chronically infected immunodeficient child and comparison with the reference strain.

Bailly J L JL Chambon M M Henquell C C Icart J J Peigue-Lafeuille H H

Journal of clinical microbiology 20000201 2

Seven sequential isolates of echovirus type 30 (EV30) were recovered over 22 months from a child with severe combined immune deficiency syndrome. The nucleotide sequences of the 5' halves of the genomes (4,400 nucleotides) of the first (S1) and last (S7) isolates were determined and compared with that of the EV30 Bastianni reference strain, also determined in this study. In genome regions P1 and P2, 101 variations were identified between the two isolates. Synonymous differences far outnumbered n ...[more]

PMID: 10655344

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Project description:BACKGROUND:Echovirus (E) 30 (E-30) meningitis is characterized by neuroinflammation involving immune cell pleocytosis at the protective barriers of the central nervous system (CNS). In this context, infection of the blood-cerebrospinal fluid barrier (BCSFB), which has been demonstrated to be involved in enteroviral CNS pathogenesis, may affect the tight junction (TJ) and adherens junction (AJ) function and morphology. METHODS:We used an in vitro human choroid plexus epithelial (HIBCPP) cell model to investigate the effect of three clinical outbreak strains (13-311, 13-759, and 14-397) isolated in Germany in 2013, and compared them to E-30 Bastianni. Conducting transepithelial electrical resistance (TEER), paracellular dextran flux measurement, quantitative real-time polymerase chain reaction (qPCR), western blot, and immunofluorescence analysis, we investigated TJ and AJ function and morphology as well as strain-specific E-30 infection patterns. Additionally, transmission electron and focused ion beam microscopy electron microscopy (FIB-SEM) was used to evaluate the mode of leukocyte transmigration. Genome sequencing and phylogenetic analyses were performed to discriminate potential genetic differences among the outbreak strains. RESULTS:We observed a significant strain-dependent decrease in TEER with strains E-30 Bastianni and 13-311, whereas paracellular dextran flux was only affected by E-30 Bastianni. Despite strong similarities among the outbreak strains in replication characteristics and particle distribution, strain 13-311 was the only outbreak isolate revealing comparable disruptive effects on TJ (Zonula Occludens (ZO) 1 and occludin) and AJ (E-cadherin) morphology to E-30 Bastianni. Notwithstanding significant junctional alterations upon E-30 infection, we observed both para- and transcellular leukocyte migration across HIBCPP cells. Complete genome sequencing revealed differences between the strains analyzed, but no explicit correlation with the observed strain-dependent effects on HIBCPP cells was possible. CONCLUSION:The findings revealed distinct E-30 strain-specific effects on barrier integrity and junctional morphology. Despite E-30-induced barrier alterations leukocyte trafficking did not exclusively occur via the paracellular route.

Project description:Echovirus 30 (E30), a member of the enterovirus B species, is a major cause of viral meningitis, targeting children and adults alike. While it is a frequently isolated enterovirus and the cause of several outbreaks all over the world, surprisingly little is known regarding its entry and replication strategy within cells. In this study, we used E30 strain Bastianni (E30B) generated from an infectious cDNA clone in order to study early entry events during infection in human RD cells. E30B required the newly discovered Fc echovirus receptor (FcRn) for successful infection, but not the coxsackievirus and adenovirus receptor (CAR) or decay-accelerating factor (DAF), although an interaction with DAF was observed. Double-stranded RNA replication intermediate was generated between 2 and 3 h postinfection (p.i.), and viral capsid production was initiated between 4 and 5 h p.i. The drugs affecting Rac1 (NSC 23766) and cholesterol (filipin III) compromised infection, whereas bafilomycin A1, dyngo, U-73122, wortmannin, and nocodazole did not, suggesting the virus follows an enterovirus-triggered macropinocytic pathway rather than the clathrin pathway. Colocalization with early endosomes and increased infection due to constitutively active Rab5 expression suggests some overlap and entry to classical early endosomes. Taken together, these results suggest that E30B induces an enterovirus entry pathway, leading to uncoating in early endosomes.IMPORTANCE Echovirus 30 (E30) is a prevalent enterovirus causing regular outbreaks in both children and adults in different parts of the world. It is therefore surprising that relatively little is known of its infectious entry pathway. We set out to generate a cDNA clone and gradient purified the virus in order to study the early entry events in human cells. We have recently studied other enterovirus B group viruses, like echovirus 1 (EV1) and coxsackievirus A9 (CVA9), and found many similarities between those viruses, allowing us to define a so-called "enterovirus entry pathway." Here, E30 is reminiscent of these viruses, for example, by not relying on acidification for infectious entry. However, despite not using the clathrin entry pathway, E30 accumulates in classical early endosomes.

Dataset Information

Genomic variations in echovirus 30 persistent isolates recovered from a chronically infected immunodeficient child and comparison with the reference strain.

Publications

Genomic variations in echovirus 30 persistent isolates recovered from a chronically infected immunodeficient child and comparison with the reference strain.

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