An inactivated novel chimeric FAdV-4 containing fiber of FAdV-8b provides full protection against hepatitis-hydropericardium syndrome and inclusion body hepatitis

Figures

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  Figure 1. Construction and identification of rFAdV-4-fiber/8b. A Schematic illustration for the construction of rFAdV-4-fiber/8b; B Western blot analysis for rFAdV-4-fiber/8b. (1) The missing ~45 kDa band in the rFAdV-4-fiber/8b lane indicated the complete removal of the FAdV-4 fiber-1 in rFAdV-4-fiber/8b; (2) The ~55 kDa band indicated that FAdV-8b fiber was successfully expressed by rFAdV-4-fiber/8b.

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  Figure 2. Replication kinetics of rFAdV-4-fiber/8b and FAdV-4. The replication kinetics of the chimeric virus rFAdV-4-fiber/8b were similar to the parental FAdV-4 in LMH cells.

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  Figure 3. Pathogenicity of the rFAdV-4-fiber/8b to 3-week-old SPF chickens. A The representative gross lesion in the heart, liver and kidney from the chickens infected with the rFAdV-4-fiber/8b was similar to chickens infected with the parental FAdV-4. B The mortality of chickens infected with FAdV-4 and rFAdV-4-fiber/8b; C The viral loads in different organs of chickens infected with the rFAdV-4-fiber/8b and parental FAdV-4 (***p-value < 0.001).

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  Figure 4. Antibody responses against FAdV-4 fiber-2 and FAdV-8b fiber in SPF chickens immunized with the inactivated rFAdV-4-fiber/8b vaccine. A The antibody responses against FAdV-4 fiber-2; B The antibody responses against FAdV-8b fiber.

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  Figure 5. Survival rates of chickens after challenging with virulent FAdV-4 (A) and FAdV-8b strain (B).

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  Figure 6. Representative post-mortem examinations of the liver, heart and kidney from chickens challenged with virulent FAdV-4 and FAdV-8b. A Accumulation of clear-yellowish effusion in the pericardial sac, swollen liver with focal haemorrhages, and edemas in the kidneys were observed in chickens from the unvaccinated and FAdV-4 challenge group. No obvious lesion was observed in chickens of the vaccinated and FAdV-4 challenge group. B Discoloration and pinpoint haemorrhages were observed in the liver of chickens in the unvaccinated and FAdV-8b challenge group. No obvious lesion was observed in chickens of the vaccinated and FAdV-8b challenge group.

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  Figure 7. Viral loads in different organs of chickens challenged with virulent FAdV-4 and FAdV-8b. Viral loads in the different tissue samples were quantified by a standard curve quantitative real-time PCR method. A The viral loads in different tissues of chickens in the FAdV-4 challenge group. B The viral loads in different tissues of chickens in the FAdV-8b challenge group. In general, the viral loads in the vaccinated group and uninfected control group were significantly lower than the unvaccinated group for both viral challenge groups (*p-value < 0.05, **p-value < 0.01, ***p-value < 0.001).

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  Figure 8. Representative histological changes in different tissues from chickens challenged with FAdV-4 and FAdV-8b. A Severe histological changes were observed in the heart, liver, kidney and the bursa of Fabricius of chickens from the unvaccinated and FAdV-4 challenge group. B Histopathological examination indicated inclusion bodies in the hepatocytes and disintegration of the bursa in the unvaccinated chickens challenged with FAdV-8b. No obvious histological changes were observed in the vaccinated chickens and uninfected chickens (HE staining, original magnification × 400).