TITLE:
The Correlation of IFN γ to the Preferential Isolation of Influenza Type B over Type A Viruses in Madin Darby Canine Kidney Cells
AUTHORS:
Timothy Byaruhanga, Bernard Bagaya, Joyce Namulondo, John Timothy Kayiwa, Barbara Namagambo, Nicholas Owor, Irene Nabukenya, Barnabas Bakamuntumaho, Julius Julian Lutwama
KEYWORDS:
Interferon Gamma, Influenza A, Influenza B, Isolation
JOURNAL NAME:
Open Journal of Medical Microbiology,
Vol.7 No.1,
February
9,
2017
ABSTRACT: The isolation of influenza viruses in Madin Darby Canine Kidney (MDCK)
cells has shown preferential isolation of a great percentage of Influenza B
strains at the first passage than Influenza A strains. During in vitro isolation of Influenza viruses,
majority of type A viruses are not confirmed as positive isolates by Hemagglutination
(HA) assay despite having higher virulence and pathogenicity versus influenza B
viruses. This study investigated the differences in IFN-γ and IL-10 cytokines secreted by MDCK cells upon exposure to the
viruses and thus provided possible answers as to why influenza type B can
easily be isolated from MDCK cells compared to influenza A. Positive influenza
viruses were inoculated onto MDCK cells. IFN-γ and
IL-10 cytokines stimulated by the viruses in MDCK cells were measured by
indirect ELISA at 1 hour, 12 hours, 48 hours and 72 hours
post inoculation (pi). A total of 46 specimens, with 23 specimens from each
virus type were analyzed. IFN-γ was significantly higher at 1 hour pi in MDCK cells for
influenza type A at p value of 0.024 than type B. No statistical significance
was observed in means of cytokine IL-10 between influenza type A and type B.
The study may show that IFN-γ is correlated to the preferential isolation of influenza type B over
type A viruses. Anti-inflammatory cytokines may not necessarily be playing a
role in the preferential growth of influenza type B, a
less virulent type over influenza type A in MDCK cells.