Biomedical subjects

Philippe de Micco

Publications and source records attributed to Philippe de Micco.

24 records · Page 2Linked to original sources

PubMed2003

Evolution of hepatitis C virus in blood donors and their respective recipients.

This paper describes the study of hepatitis C virus (HCV) evolution in the largest cohort of HCV-infected blood donors (BDs)/blood recipients (BRs) reported to date (25 pairs). A molecular analysis of partial sequences in the E1 (envelope) and NS5-B (polymerase) genes was performed. Phylogenetic reconstruction showed that the evolution of dominant strains was qualitatively and quantitatively different in BDs and BRs. The evolutionary rate was significantly higher in BRs, in which, in addition, most substitutions observed were antonymous. These findings corroborate the hypothesis that a large part of virus evolution - which was evaluated to be equivalent to approximately 20 years of chronic evolution - is acquired during the early phase of infection. These findings should be taken into account for the modelling of the long-term evolution of HCV and their possible contribution to improve our understanding of HCV natural history is discussed.

Blood Donors↗

PubMed2003

Recombinant VP7-based enzyme-linked immunosorbent assay for detection of immunoglobulin G antibodies to Colorado tick fever virus.

VP6, VP7, VP9, VP10, VP11, and VP12 of Colorado tick fever virus (CTF virus), a virus member of the genus Coltivirus, family Reoviridae, were expressed in bacteria with the pGEX-4T-2 vector. A partial sequence of VP7 (designated pVP7) was chosen to elaborate an enzyme-linked immunosorbent assay (ELISA) for detecting anti-CTF virus immunoglobulin G (IgG) antibodies in humans. This was based on two observations: (i) among all expressed proteins, pVP7 showed the highest immunoreactivity to an anti-CTF virus hyperimmune ascitic fluid; (ii) to provide the highest selectivity of antibody detection, the expressed sequence was chosen within a region which is highly divergent (49% amino acid identity) from the homologous sequence of another coltivirus, the Eyach virus. The pVP7 ELISA was evaluated with 368 serum samples from French blood donors and found to provide 98.1% specificity. Assays with the Calisher set of human serum samples, positive for anti-CTF virus antibodies (C. H. Calisher, J. D. Poland, S. B. Calisher, and L. A Warmoth, J. Clin. Microbiol. 22:84-88, 1985), showed that the pVP7 ELISA provided 100% sensitivity for the tested population. After elaboration of recombinant-protein-based ELISAs for diagnosis of infections with members of the viral genera Orbivirus, Orthoreovirus, and Rotavirus, it was shown that a recombinant protein could be used to detect antibodies to the human pathogen Colorado tick fever virus.

Antibodies, Viral↗

PubMed2002

High genetic diversity revealed by the study of TLMV infection in French hemodialysis patients.

TT virus-like minivirus (TLMV) was recently discovered as a human circovirus. Little is known about its natural history and molecular epidemiology. A study of TLMV infection is described in a population of French hemodialysis patients. TLMV DNA was tested by seminested PCR system located in the noncoding region in 81 patients divided into seven groups according to the origin of their renal disease. Quantitation of TLMV DNA in serum was carried out. Sequences from 28 patients were compared with 40 sequences retrieved from databases and 53 TLMV sequences cloned from the serum of a single patient. The prevalence of TLMV DNA in hemodialysis patients was 95.1%. In this study, 24 samples (29.6%) presented viral loads of > 125 equivalents of plasmid (Ep)/ml, and only 6 (7.8%) had viral loads of > 125 x 10(2) Ep/ml. A significant correlation (P < 0.029) was found between viral loads of > 125 x 10(2) Ep/ml and the neoplastic origin of end-stage renal disease. Analysis of 53 sequences cloned from a single individual demonstrated high sequence variability, as shown by the genetic distance of 40.2%. This genetic distance is comparable to that between the most divergent sequences of TLMV reported to date (43.5%). These data suggest that TLMV viral load is possibly related to the level of immunocompetence of hemodialysis patients; the genetic diversity of TLMV is extremely high; and co-infection by different strains is possible.

Adult↗

PubMed2002

Common evolutionary origin of aquareoviruses and orthoreoviruses revealed by genome characterization of Golden shiner reovirus, Grass carp reovirus, Striped bass reovirus and golden ide reovirus (genus Aquareovirus, family Reoviridae).

Full-length and partial genome sequences of four members of the genus Aquareovirus, family Reoviridae (Golden shiner reovirus, Grass carp reovirus, Striped bass reovirus and golden ide reovirus) were characterized. Based on sequence comparison, the unclassified Grass carp reovirus was shown to be a member of the species Aquareovirus C. The status of golden ide reovirus, another unclassified aquareovirus, was also examined. Sequence analysis showed that it did not belong to the species Aquareovirus A or C, but assessment of its relationship to the species Aquareovirus B, D, E and F was hampered by the absence of genetic data from these species. In agreement with previous reports of ultrastructural resemblance between aquareoviruses and orthoreoviruses, genetic analysis revealed homology in the genes of the two groups. This homology concerned eight of the 11 segments of the aquareovirus genome (amino acid identity 17-42%), and similar genetic organization was observed in two other segments. The conserved terminal sequences in the genomes of members of the two groups were also similar. These data are undoubtedly an indication of the common evolutionary origin of these viruses. This clear genetic relatedness between members of distinct genera is unique within the family Reoviridae. Such a genetic relationship is usually observed between members of a single genus. However, the current taxonomic classification of aquareoviruses and orthoreoviruses in two different genera is supported by a number of characteristics, including their distinct G+C contents, unequal numbers of genome segments, absence of an antigenic relationship, different cytopathic effects and specific econiches.

Amino Acid Sequence↗

PubMed2001

Genetic analysis of full-length genomes and subgenomic sequences of TT virus-like mini virus human isolates.

The phylogenetic relationship between the complete genomic sequences of ten Japanese and one French isolate of TT virus-like mini virus (TLMV) was investigated. Analysis of the variability of the nucleotide sequences and the detection of signature patterns for overlapping genes suggested that ORFs 1 and 2 are probably functional. However, this was not the case for a putative third ORF, ORF3. Throughout the viral genome, several nucleotide or amino acid motifs that are conserved in circoviruses such as TT virus (TTV) and chicken anaemia virus were identified. Phylogenetic analysis distinguished three main groups of TLMV and allowed the identification of putative recombination breakpoints in the untranslated region. TLMV genomes were detected by PCR in the plasma of 38/50 French blood donors tested and were also identified in peripheral blood mononuclear cells, faeces and saliva. A phylogenetic study of 37 TLMV strains originating from France, Japan and Brazil showed that groupings were not related to geographical origin.

Base Composition↗

PubMed2001

Complete sequence characterization of the genome of the St Croix River virus, a new orbivirus isolated from cells of Ixodes scapularis.

An orbivirus identified as St Croix River virus (SCRV) was isolated from cells of Ixodes scapularis ticks. Electron microscopy showed particles with typical orbivirus morphology. The SCRV genome was sequenced completely and compared to previously characterized orbivirus genomes. Significant identity scores (21-38%) were detected between proteins encoded by segments S1, S2, S4, S5, S6, S8, S9 and S10 of SCRV and those encoded by segments S1, S3, S4, S5, S6, S7, S9 and S10, respectively, of Bluetongue virus (BTV), the prototype orbivirus species. The protein encoded by SCRV genome segment 3 (VP3) is thought to be the equivalent of VP2 of BTV. Segment 7 encodes a protein homologous to non-structural protein NS2(ViP) of BTV. Analysis of VP1(Pol) (segment 1) shows that SCRV is an orbivirus, distantly related to the other sequenced species. Blot hybridizations and sequence comparisons of the conserved protein encoded by genome segment 2 (the T2 subcore shell protein) with previously identified orbiviruses confirm that SCRV is a distinct orbivirus species, unrelated to another tick-borne species, Great Island virus. The presence of SCRV in cells prepared from tick eggs suggests that transovarial transmission of SCRV may occur in ticks.

Animals↗