Research paperEvaluation of influenza vaccine-immunogenicity in cell-mediated immunity

•We developed a simple method to measure cell-mediated immunity (CMI).•We evaluated vaccination-induced CMI by measuring changes in the interferon-gamma (IFN-γ) level.•The IFN-γ level increased at least 1.5 times in 57% (13/23) of cases in response to H3N2.•In 4 subjects who developed influenza (H3N2), IFN-γ did not increase by 1.5 times.•Our work presents an effective alternate method to testing of humoral immunity.

The immunological effect of influenza vaccines cannot be evaluated accurately using an antibody titer. Therefore, we used a new method that measures cell-mediated immunity to investigate changes in the amount of interferon-gamma (IFN-γ) produced after vaccination in response to the vaccine antigen. The study was conducted during the 2014-2015 influenza season in 23 adults, using a vaccine that contained three types of antigen. The IFN-γ level increased by at least 1.5 times in 65% (15/23) of cases in response to the H1N1 antigen, in 57% (13/23) of cases in response to the H3N2 antigen, and in 57% (13/23) of cases in response to the B antigen. During the study period, 4 subjects developed type A influenza. Our data showed that the IFN-γ level did not increase by 1.5 times in these subjects. We propose that the efficacy of influenza vaccines may be evaluated by measuring changes in the level of IFN-γ produced in response to influenza vaccine.