Background Most of the current approaches to influenza vaccine design focus on antibodies against influenza hemagglutinin (HA). However, these influenza vaccines typically provide strain-specific protection against mostly homologous subtypes. There is an urgent need to develop a universal vaccine that confers cross-protection against influenza viruses. Of note, the HA stalk domain (HAs) is a new target for such an influenza vaccine.
Results Recombinant L.lactis/pNZ8150-pgsA-HAs constructed in which pgsA was used as an anchor protein and investigated the immunogenicity of HAs, in the mouse model by oral administration without the use of a mucosal adjuvant. Mice were orally vaccinated with L.lactis/pNZ8150-pgsA-HAs, and then produced significant humoral and mucosal immune responses. Importantly, L.lactis/pNZ8150-pgsA-HAs provided significant cross-protection against H5N1, H3N2 or H1N1 virus infection.
Conclusions Our data support the hypothesis that HAs presented on the surface of L. lactis can provide cross-protective immunity against influenza A viruses. Taken together, these findings suggest that L.lactis/pNZ8150-pgsA-HAs can be considered an alternative approach to developing a novel universal vaccine during an influenza A pandemic.