PT  - JOURNAL ARTICLE
AU  - Irina Falynskova
AU  - Irina Leneva
AU  - Andrej Egorov
AU  - Aleksandr Poddubikov
AU  - Reingard Grabherr
AU  - Miriam Klausberger
TI  - Protective efficacy and antigenicity of influenza HA-VLPs in a murine model of postinfluenza bacterial pneumonia
AID  - 10.1183/13993003.congress-2019.PA4557
DP  - 2019 Sep 28
TA  - European Respiratory Journal
PG  - PA4557
VI  - 54
IP  - suppl 63
4099  - http://erj.ersjournals.com/content/54/suppl_63/PA4557.short
4100  - http://erj.ersjournals.com/content/54/suppl_63/PA4557.full
SO  - Eur Respir J2019 Sep 28; 54
AB  - Background: Secondary bacterial pneumonia is an important cause of influenza-associated death in the case of lacking anti-influenza immunity, such as in the event of a vaccine mismatch.Aim: We studied the protective efficacy and antigenicity of influenza HA-VLPs in a lethal murine model of postinfluenza S.pneumoniae pneumonia imitating the situation of a vaccine match or mismatch.Methods: BALB/c mice received two vaccinations with insect-cell expressed influenza HA-VLPs (0,05 or 0,01 µg HA/mouse). At day 21 post vaccination, mice were infected with a homologous A/PR/8/34/RG (H1N1) or heterologous NIBRG-121xp (H1N1) (A/PR/8/34 reassortant with HA and NA from A/California/4/2009) influenza virus followed by S. pneumoniae infection 7 days post influenza. Antigenicity was estimated by HAI-assays, protective efficacy was assessed by morbidity and mortality and viral and bacterial murine pulmonary titers.Results: Mice receiving a single low dose of 0.05 µg HA-VLPs were fully protected from mortality as well as viral and bacterial replication in the lung when a vaccine-matched influenza virus was used for infection before S.pneumoniae challenge. When using a heterologous influenza virus before bacterial superinfection the survival rate dropped to 25% and bacterial pulmonary titers were only slightly lower than in non-vaccinated mice.Conclusions: Postinfluenza S.pneumoniae complications may be limited by a potent anti-influenza HA immunity. In this respect, VLPs are an attractive vaccine platform and tool to study the role of influenza-specific immunity in the prevention of postinfluenza bacterial pneumonia. This work was supported by the RSF-FWF grant No 18-45-05002FootnotesCite this article as: European Respiratory Journal 2019; 54: Suppl. 63, PA4557.This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only).