High interferon type I responses in the lung, plasma and spleen during highly pathogenic H5N1 infection of chicken
Résumé
This study shows that high pathogenic H5N1 influenza virus infection of chicken induced high levels of bioactiveinterferon type I in the lung (4.3 × 105 U/mg tissue), plasma (1.1 × 105 U/mL), and spleen (9.1 × 105 U/mg tissue).In contrast, a low pathogenic attenuated H5N1 vaccine strain only induced approximately 24 times less IFN in thelung, 441 times less in the spleen and 649 less in the plasma. This was in the same range as a reassortant carryingthe HA from the vaccine strain and the remaining genes from the high pathogenic virus. On the other hand, areassortant virus with the HA from the high pathogenic H5N1 with the remaining genes from the vaccine strainhad intermediate levels of IFN. The level of interferon responses related to the viral load, and those in the spleenand blood to the spread of virus to lymphoid tissue, as well as disease severity. In vitro, the viruses did not induceinterferon in chicken embryonic fibroblasts, but high levels in splenocytes, with not clear relationship topathogenicity and virulence. This, and the responses also with inactivated viruses imply the presence ofplasmacytoid dendritic cell-like leukocytes within the chicken immune system, possibly responsible for the highinterferon responses during H5N1 infection. Our data also indicate that the viral load as well as the cleavability ofthe HA enabling systemic spread of the virus are two major factors controlling systemic IFN responses in chicken.
Domaines
Sciences du Vivant [q-bio]
Origine : Fichiers produits par l'(les) auteur(s)
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