Background: The outbreaks of new antigenic variants of influenza viruses in human populations have increased necessity the improvement of controlling programs. Influenza vaccines are formulated with adjuvant to enhance and direct the host immune responses. Currently, much effort is devoted to designing molecular adjutants. Hemokinin-1 (HK-1) activates T and B cells for proliferation, survival, differentiation into plasma cells, and antibody production. In this study, the effect of HK-1 as a molecular adjuvant for inducing humoral immune response against influenza virus was investigated.

Materials and Methods: The HK-1 coding sequence was cloned into pcDNA3.1 vector and used as adjuvant. Groups of mice were immunized with an inactivated influenza vaccine formulated with HK-1. The sera of vaccinated mice were collected prior to priming and boosting injections and at defined weeks, and analyzed with serological assays.

Results: The results showed that HK-1 was able to increase antibody titer against virus vaccine. The mice immunized with the adjuvanted vaccine produced higher antibody titers against influenza comparing to vaccine alone immunized group. Number of boosting had no effect on the enhancing of antibody titer.

Conclusion: These data revealed that HK-1 as a molecular adjuvant induces stronger humoral and memory responses against influenza immunization.