Characterization of avain metapneumovirus subgroup C isolated from chickens in Beijing, China

Figures

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  Figure 1. Infection of aMPV/C strain BJ17 in cultured Vero cells. (A) Cytopathic effects were observed in the Vero cells after strain BJ17 infection. (B) Vero cells at 72 h following aMPV/C infection were incubated with a rabbit antibody raised against aMPV N protein polypeptide followed by incubation with a FITC-conjugated anti-rabbit IgG antibody. Vero cells expressing N protein stained in green. (C) aMPV/C-infected cell lysates at various time points after infection were collected, electrophoresed by SDS-PAGE, and immunoblotted for analysis of the N protein expression. β-actin was acted as the loading control.

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  Figure 2. Phylogenetic analysis of aMPV viruses based upon the nucleotide sequences of the nucleoprotein gene by MAGE7. Isolate BJ17 is highlighted by a marked symbol. The GenBank accession number of each aMPV sequence is listed as the accession number in parenthesis.

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  Figure 3. Growth kinetics of the aMPV/C strain BJ17 in cultured cells. Vero cells were infected with BJ17 at an MOI of 0.1 and collected at the indicated time points for the viral titration. Virus titers were shown as TCID50/mL, and values are expressed as the mean ± SD of the results of triple independent experiments.

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  Figure 4. aMPV shedding in oropharyngeal swabs of chickens inoculated with strain BJ17 was quantitatively detected by real-time RT-PCR. The values are expressed as the means of the results for all 15 BJ17-inoculated chickens at 3, 5, and 7 dpi; error bars represent the standard deviations.

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  Figure 5. Histological lesions of respiratory tract samples from the BJ17-inoculated SPF chickens. (A) Trachea section from a non-inoculated chicken shows intact ciliated epithelium. (B) Trachea section of a BJ17-inoculated chicken displaying loss of cilia, rupture of architenture, and infiltrated inflammatory cells in the epithelium and submucosa. (C) Lung section from a non-inoculated chicken shows no overt inflammation. (D) Lung section of a BJ17-inoculated chicken displaying infiltration of inflammatory cells, such as lymphocytes, disffused heterophils and macrophages in the lung. Bars, 20 μm.

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  Figure 6. Immunohistochemical staining of respiratory tract samples from the aMPV/C strain BJ17-inoculated SPF chickens. Nasal turbinate (A), tracheae (C), and lung tissue (E) from a non-inoculated chicken displays no positive cells for aMPV/C antigen. Nasal turbinate (B), tracheae (D), and lung tissue (F) of a BJ17-inoculated chicken displays large amount of positive cells for aMPV/C antigen. Bars, 20 μm.