J.-F. Cantaloube

Determination and phylogenetic analysis of partial sequences from TT virus isolates.

Sera from French in-patients were tested for the presence of the TT virus (TTV) genome using PCR and degenerate primers located in ORF1. Thirty-six sequences were determined and compared with those deposited in databases, revealing a high degree of genetic variability between TTV isolates (up to 47% for amino acid sequences). Phylogenetic analysis demonstrated the existence of three main groups corresponding to the previously described genotypes 1 and 2 and to a new genotype 3. Isolates could be assigned to distinct genotypes if their genetic distance was > 27%. No comparable genetic criteria were found for the definition of sub-types in the region studied. A 15-31 month follow-up of three haemodialysis patients proved the existence of chronic infection by TTV. In one patient, two strains belonging to different genotypes were detected at the same time. Sequences of both ORF1 and ORF2 remained unchanged for a given strain during the follow-up.

High prevalence of TT virus infection in French blood donors revealed by the use of three PCR systems

BACKGROUND: The purpose of this study was to determine the prevalence of TT virus (TTV) infection in voluntary blood donors in Southeastern France.

Genus Coltivirus (family Reoviridae): genomic and morphologic characterization of Old World and New World viruses

Summary. We report a genomic and morphologic study of the European Eyach (EYA) virus (genus Coltivirus, family Reoviridae) and a comparative analysis with the American Colorado tick fever (CTF) virus (the type species of the genus). The previously established, but distant, antigenic relationship between these viruses was strengthened by genetic findings (presence of cognate genes, amino acid identity between 55 and 88%, similar conserved terminal motifs, suspected read-through phenomenon in segment 9 of both viruses) and by indistinguishable ultramicroscopic morphologies. Moreover, putative constitutive modifying enzyme activities were suspected to be carried out by homologous viral proteins (RNA-dependent RNA polymerase, methyl/guanylyl transferase, NTPase).These findings, together with the comparative analysis to genomes of south-east Asian isolates, support the recent classification of arboviruses with 12 segments of dsRNA within two distinct genera (genus Coltivirus and genus Seadornavirus) and raise interesting questions about the evolutionary origins of coltiviruses. The previously proposed hypothesis that EYA virus was derived from an ancestral virus introduced in Europe with the migration of lagomorphs from North-America, would imply a divergence date between American and European isolates of over 50 million years ago (MYA). This analysis allows for the first time to propose an evolutionary rate for virus dsRNA genomes which was found to be in the order of 10−8 to 10−9 mutations/nt/year, a rate similar to that of dsDNA genomes.

COMPARATIVE SEQUENCE ANALYSIS OF AMERICAN, EUROPEAN AND ASIAN ISOLATES OF VIRUSES IN THE GENUS COLTIVIRUS

In this study, the basis for the classification of virus isolates grouped within the genus Coltivirus, family Reoviridae, is discussed. Sequences of dsRNA segments from American (segments 9-12), European (segment 12) and Asian (segments 7-12) isolates were characterized and polythetic criteria were defined for their taxonomic classification. These criteria (including sequence analysis) permitted the different species to be distinguished and classified into two groups. In both groups, subgroups were defined according to the degree of homology between the genomic sequences. American and European isolates are classified within group A, which includes subgroups A1 (Colorado tick fever virus species) and A2 (Eyach virus species). Asian isolates are classified in group B, which includes subgroups B1 (JKT-7075 virus species) and B2 (JKT-6423 virus species). The proteins encoded by the sequenced genomic segments were analysed. This allowed the identification of dsRNA binding domains in the proteins encoded by segment 8 of subgroup B1 isolates and segment 12 of subgroup B2 isolates. A conserved pattern of amino acids in segment 7 of group B isolates matched sequences found in the catalytic domains of protein kinases.

GBV-C/hepatitis G virus (HGV) RNA load in immunodeficient individuals and in immunocompetent individuals

The aim of this study was to establish the mean plasma GBV‐C/ hepatitis G virus (HGV) RNA load in groups of GBV‐C/HGV‐infected individuals with varied immune status and to determine the most frequent patterns of evolution of the plasma GBV‐C/HGV RNA load over time during the natural history of infection. The mean plasma GBV‐C/HGV RNA load observed was, from the lowest to the highest: 5.21 log in immunodepressed multiply‐transfused patients, 6.45 log in HIV‐positive individuals, 6.66 log in immunocompetent multiply‐transfused patients, and 6.71 log in blood donors. The difference was significant between the four groups (P < 0. 0001). The most frequent pattern of evolution of the plasma GBV‐C/HGV RNA load was as follows: after the primary GBV‐C/HGV infection, the viral load was elevated from the onset; then, a high, persistent and relatively steady viral RNA level was the rule; and when it occurred, the loss of viremia was not preceded by a decrease before recovery from GBV‐C/HGV infection. J. Med. Virol. 59:32–37, 1999.

Molecular characterization of genotype 2 and 4 hepatitis C virus isolates in French blood donors

The subtype distribution of 142 genotype 2 and 97 genotype 4 hepatitis C virus (HCV) isolates from the sera of 1,319 volunteer blood donors in France was determined by gene sequencing and by phylogenetic analysis of the NS5B region and E1 envelope. Findings underlined a wide range of subtypes in both genotypes, that is, 20 in HCV‐2 and 11 in HCV‐4. Eighteen of these 31 subtypes had not been defined previously. Some subtypes, that is, 2a, 2b, 2c, 2i, 2k, 4a, and 4d, showed numerous strains while subtypes in donors from West Africa or Central Africa showed an endemic profile with only a few strains. A Bayesian coalescence approach was used to estimate the demographic history of each HCV subtype. The estimated mean dates of the most recent common ancestors (MRCA) were 1,889 (confidence interval (CI), 1,842–1,930) for HCV‐2a, 1,886 (CI, 1,843–1,921) for HCV‐2b, 1,791 (CI, 1,699–1,848) for HCV‐2c, 1,846 (CI, 1,803–1,878) for HCV‐2i, 1,911 (CI, 1,879–1,937) for HCV‐4a, and 1,957 (CI, 1,943–1,967) for HCV‐4d. The period of spread for subtype 2b, 2c, and 2i was between 1900 and 1960 whereas rapid exponential spread for subtype 2a, 4a, and 4d occurred in the 1960s. The inferred histories of population growth indicated that transmission rates differed according to HCV subtype. These results may help to predict the future burden of HCV in France. J. Med. Virol. 80:1732–1739, 2008.

Inactivation of a European strain of West Nile virus in single- donor platelet concentrate using the INTERCEPT blood system

Background and Objective  In order to prevent West Nile virus (WNV) contaminations by transfusion, the French National Blood Service decided to evaluate the INTERCEPT Blood Systems efficiency on a European strain.

Molecular analysis of HCV type 1 to 5 envelope gene: application to investigations of posttransfusion transmission of HCV

BACKGROUND: Until 1990, HCV infection was common in transfused patients, resulting in more than 200,000 cases of posttransfusion hepatitis C in France alone. A molecular method that permits the investigation of posttransfusion hepatitis C infections is presented.

High prevalence of GB-C/hepatitis G virus in a Brazilian population with helminth infection

A study of GB‐C virus/Hepatitis G virus (GBV‐C/HGV) infection was carried out in a rural population of Northeastern Brazil, in which the prevalence of schistosomiasis is 80–90%. Despite the absence of parenteral risk exposure, the prevalence of GBV‐C/HGV markers of infection was found to be unusually increased: viremia, 16.4%; specific antibody, 18.3%. It is therefore suspected that helminth infection influenced the immune response to GBV‐C/HGV infection by shifting the balance of cytokine responses from Th1 to Th2, resulting in a delayed viral clearance. Phylogenetic analysis of viral isolates did not provide evidence for high rates of sexual or mother‐to‐infant viral transmission. The study revealed that viral strains belonged to types 1 and 2 only (predominant in Africa and Europe, respectively), suggesting that GBV‐C/HGV was introduced into the New World by white conquerors and black slaves since the 16th century. J. Med. Virol. 56:310–315, 1998.

Gastrointestinal hormone mRNA expression in human colonic adenocarcinomas, hepatic metastases and cell lines

Aims—(1) To investigate the expression of the four main hormones of the digestive tract by performing reverse transcription polymerase chain reaction (RT-PCR) on a series of samples, comprising tumoral and healthy colonic tissues, hepatic metastases and colonic cell line samples; and (2) to study the patterns of labelling obtained with serological and morphological markers. Methods—After extraction and reverse transcription, gastrin, somatostatin, cholecystokinin (CCK) and transforming growth factor α (TGFα) mRNAs were detected by PCR and nested PCR using specific primers. The corresponding proteins were detected by immunohistochemistry. Results—The cell lines expressed all four mRNAs. Gastrin mRNA was present in most tumoral and metastatic samples, while the somatostatin transcript was detected in all samples and was frequently overexpressed in the normal colon. TGFα mRNA was expressed systematically in tumours of the right and transverse colon, but not in those located in the left colon; the expression of CCK mRNA was systematically absent in the left colon. Conclusions—The data presented here shed some light on the transcriptional events involved in the production of the various hormones present in the gastrointestinal tract, in both healthy and tumoral tissues. The various mRNAs expressed in cell lines are therefore not systematically expressed in the human pathology.