Isolates 007Lm, S124C and Ac961 and a vero cell-adapted Onderstepoort strain of canine distemper viruses (CDV) were examined for stability after passages in verocells expressing the canine signaling lymphocyte activa...
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Isolates 007Lm, S124C and Ac961 and a vero cell-adapted Onderstepoort strain of canine distemper viruses (CDV) were examined for stability after passages in verocells expressing the canine signaling lymphocyte activation molecule (dogSLAM, the intrinsic receptor to CDV). These viruses passage once in verocells expressing dogSLAM (vero-dst) cells (original) and after 20 passages (20p) were compared by using sequence analyses and growth characteristics. All four strains of 20p grew well and were slightly better than their originals. The 20p viruses developed a cytopathic effect slightly lower than the original strains. A few changes in amino acids in the H gene were between the 20p and the original viruses, but the sites of changes were not specific. Fragments of P, M and L genes of all strains showed no nucleotide changes after the passages. These results showed that: (1) passages of CDVs in vero-dst cells induced amino acid changes only in the H gene, not in the P, M and L genes, unlike in a previous study with verocells;(2) passages did not markedly affect the growth characteristics of every viral strain. These results indicate that verocells expressing canine SLAM allow the isolation and passaging of CDV without major changes in viral genes. (c) 2006 Elsevier B.V. All fights reserved.
Fresh samples of lymph node, lung and cerebrum taken post mortem from dogs no. 1, 2 and 3 yielded canine distemper virus (CDV) strains 007 Lm, 009 L and 011 C, respectively. These were titrated on verocells stably ex...
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Fresh samples of lymph node, lung and cerebrum taken post mortem from dogs no. 1, 2 and 3 yielded canine distemper virus (CDV) strains 007 Lm, 009 L and 011 C, respectively. These were titrated on verocells stably expressing canine signalling lymphocyte activation molecule (SLAM;vero-dst cells). Growth curves of the three strains were produced by titration of the released virus and cell-associated virus at various timepoints. All three isolates, especially 007 Lm, grew well on vero-dst cells. The titres of cell-associated virus of two strains (009 L and 011 C) were clearly lower than those of virus released into the culture supernate. The results indicate that vero-dst cells are not only useful for primary isolation but also efficient for titrating virus from fresh tissues and for the study of growth profiles of recent CDV isolates. (c) 2005 Elsevier Ltd. All rights reserved.
The pathogenesis of a new isolate of canine distemper virus (CDV), strain 007Lm, was investigated from lymph node tissue by using verocells that express canine signalling lymphocyte activation molecules with a tag (V...
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The pathogenesis of a new isolate of canine distemper virus (CDV), strain 007Lm, was investigated from lymph node tissue by using verocells that express canine signalling lymphocyte activation molecules with a tag (vero-dst) in dogs. Two CDV sero-negative Beagle dogs were inoculated intranasally and intraconjunctively with a virus suspension. Both infected dogs showed clinical signs of severe bloody diarrhea, conjunctivitis, ocular discharge, nasal discharge and coughing, lymphopenia, fever and weight loss. Titers of CDV-IgM and CDV-IgG in the blood were measured. CDV was detected by using reverse transcriptase-PCR and was recovered in swabs from one dog from 9 days and from the other dogs from 10 days after inoculation. Molecular and phylogenetic analyses of H and P genes showed that nucleotide and amino acid sequences of these genes of strain 007Lm after isolation in vero-dst cells are identical to those of the original virus from fresh tissue and that strain 007Lm joins to the Asia 2 group cluster of CDV strains that is distinct from other clusters. These results indicate that (1) CDV strain 007Lm isolated in vero-dst cells is virulent, (2) nucleotide and amino acid sequences of H and P genes of strain 007Lm do not change after isolation in vero-dst cells compared with the original virus from fresh tissue and (3) strain 007Lm isolated from a vaccinated dog belongs to a cluster far from the vaccine strains in the phylogenetic trees of H and P genes. (c) 2005 Elsevier B.V. All rights reserved.
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