@article{10.37349/ei.2025.1003230,
abstract = {Aim: Develop A/H1N1pdm09-based live attenuated influenza vaccines (LAIVs) presenting chimeric hemagglutinin (HA) fused to fragments of Streptococcus pneumoniae (PspA, Spr1875) or S. agalactiae (ScaAB) to elicit combined anti-influenza and anti-bacterial immunity. Methods: Recombinant LAIVs were generated by reverse genetics. Replicative fitness was measured in embryonated chicken eggs (CE; log10 EID50/0.1 mL, n = 5 per delution) and MDCK cells (log10 TCID50/mL, n = 5). BALB/c mice (n = 20 per group; serology n = 6 per group; lung titers n = 5 per group) received intranasal 106 EID50. Systemic IgG and mucosal IgA to influenza and to the recombinant pneumococcal peptide were quantified by ELISA (GMT ± SD). Early cytokine responses were profiled in THP-1 cells. Results: All recombinant strains replicated in CE at 33°C but were temperature-sensitive at 39°C. H1-ScaAB retained relatively high replication and exhibited a cold-adapted phenotype despite a large N-terminal insert. In MDCK cells, H1-PspA showed significantly reduced replication compared with the parental LAIV. In mouse lungs, replication on day 3 post-immunization was significantly lower for H1-ScaAB and H1-PspA compared with the parental LAIV strain (p < 0.05). The parental LAIV induced robust systemic anti-influenza IgG and, uniquely for H1-ScaAB, significant mucosal anti-influenza IgA (p < 0.05). H1-Spr generated stronger antibody responses to the inserted pneumococcal peptide (p < 0.05). THP-1 assays revealed construct-specific cytokine patterns (unmodified H1N1: highest IFN-α; H1-Spr: elevated IL-6; H1-ScaAB: greatest MCP-1). Conclusions: Multiple A/H1N1pdm09-based recombinant LAIVs with chimeric HA can replicate in eggs and murine respiratory tract and induce dual influenza/pneumococcal antigen responses. Expanded biophysical validation, functional antibody assays and challenge studies are needed to optimize insert design without compromising viral fitness.},
author = {Desheva, Yulia and Mayorova, Irina and Rekstin, Andrey and Kudar, Polina and Trulioff, Andrey and Petrachkova, Daria and Kotomina, Tatiana and Kopylova, Nina and Matushkina, Anastasiia and Sokolovsky, Daniil and Guzenkov, Danila and Isakova-Sivak, Irina},
doi = {10.37349/ei.2025.1003230},
journal = {Exploration of Immunology},
elocation-id = {1003230},
title = {Recombinant influenza A/H1N1pdm09 vaccine expressing streptococcal surface epitope for dual protection},
url = {https://www.explorationpub.com/Journals/ei/Article/1003230},
volume = {5},
year = {2025}
}