Author(s)

Timothy Byaruhanga^1*, Bernard Bagaya², Joyce Namulondo¹, John Timothy Kayiwa¹, Barbara Namagambo¹, Nicholas Owor¹, Irene Nabukenya¹, Barnabas Bakamuntumaho¹, Julius Julian Lutwama¹

¹Department of Arbovirology, Uganda Virus Research Institute, Entebbe, Uganda.
²College of Health Sciences, Makerere University, Kampala, Uganda.

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.

Interferon Gamma, Influenza A, Influenza B, Isolation

Byaruhanga, T. , Bagaya, B. , Namulondo, J. , Kayiwa, J. , Namagambo, B. , Owor, N. , Nabukenya, I. , Bakamuntumaho, B. and Lutwama, J. (2017) The Correlation of IFN γ to the Preferential Isolation of Influenza Type B over Type A Viruses in Madin Darby Canine Kidney Cells. Open Journal of Medical Microbiology, 7, 12-28. doi: 10.4236/ojmm.2017.71002.