Inactivation of Human Influenza Virus Using Gamma Irradiation

We need the next-generation of whole-inactivated influenza vaccines to create stronger cross-protection against different influenza subtypes. This research aimed to apply the inactivation process of the influenza virus through gamma radiation as a candidate for the development of whole-inactivated vaccines.

 The influenza virus strain A/PR/8/34 (A/Puerto Rico/8/34 [H1N1]) was propagated in Madin-Darby Canine Kidney (MDCK) epithelial cells. After ultrafiltration, the virus infectivity titer was calculated by 50% Tissue Culture Infectious Dose (TCID 50%) method based on the Karber formula. Alternatively, the gamma cell-220 was applied for virus inactivation via gamma rays. The D10 value factor and optimum dose of virus inactivation were calculated based on the dose/survival curve and the initial viral titer. In addition, antigenic properties of irradiated viruses compared to un-irradiated viruses and complete inactivation of the irradiated samples with optimum dose were also evaluated by hemagglutination assay and safety test, respectively.

 The Research Ethics Committee of Islamic Azad University, Tehran Medical Branch, Iran approved this study (Code: IR.IAU.TMU.REC.1397.309).

 According to the concentrated virus titer (TCID50: 105.75/ml) and dose/survival curve, the D10 value factor and optimum dose of virus inactivation were calculated at 4.878 and 28.048 kGy, respectively. On the other hand, owing to the results obtained from the safety test and hemagglutination assay, the optimum dose of virus inactivation was determined to be 28 kGy by maintaining the antigenic properties.

 Gamma radiation appears to be a good candidate for vaccine development through maintaining the antigenic structures.