tetano
Editor, Senior Moderator
Vet Res
. 2024 May 21;55(1):65.
doi: 10.1186/s13567-024-01319-5. Pathogenicity and escape to pre-existing immunity of a new genotype of swine influenza H1N2 virus that emerged in France in 2020
Céline Deblanc[SUP] 1 [/SUP], Stéphane Quéguiner[SUP] 2 [/SUP], Stéphane Gorin[SUP] 2 [/SUP], Gautier Richard[SUP] 2 [/SUP], Angélique Moro[SUP] 3 [/SUP], Nicolas Barbier[SUP] 2 [/SUP], Gérald Le Diguerher[SUP] 3 [/SUP], Frédéric Paboeuf[SUP] 3 [/SUP], Séverine Hervé[SUP] 2 [/SUP], Gaëlle Simon[SUP] 2 [/SUP]
Affiliations
In 2020, a new genotype of swine H1N2 influenza virus (H1[SUB]av[/SUB]N2-HA 1C.2.4) was identified in France. It rapidly spread within the pig population and supplanted the previously predominant H1[SUB]av[/SUB]N1-HA 1C.2.1 virus. To characterize this new genotype which is genetically and antigenically distant from the other H1[SUB]av[/SUB]Nx viruses detected in France, an experimental study was conducted to compare the outcomes of H1[SUB]av[/SUB]N2 and H1[SUB]av[/SUB]N1 infections in pigs and evaluate the protection conferred by the only inactivated vaccine currently licensed in Europe containing an HA 1C (clade 1C.2.2) antigen. Infection with H1[SUB]av[/SUB]N2 induced stronger clinical signs and earlier shedding than H1[SUB]av[/SUB]N1. The neutralizing antibodies produced following H1[SUB]av[/SUB]N2 infection were unable to neutralize H1[SUB]av[/SUB]N1, and vice versa, whereas the cellular-mediated immunity cross-reacted. Vaccination slightly altered the impact of H1[SUB]av[/SUB]N2 infection at the clinical level, but did not prevent shedding of infectious virus particles. It induced a cellular-mediated immune response towards H1[SUB]av[/SUB]N2, but did not produce neutralizing antibodies against this virus. As in vaccinated animals, animals previously infected by H1[SUB]av[/SUB]N1 developed a cross-reacting cellular immune response but no neutralizing antibodies against H1[SUB]av[/SUB]N2. However, H1[SUB]av[/SUB]N1 pre-infection induced a better protection against the H1[SUB]av[/SUB]N2 infection than vaccination, probably due to higher levels of non-neutralizing antibodies and a mucosal immunity. Altogether, these results showed that the new H1[SUB]av[/SUB]N2 genotype induced a severe respiratory infection and that the actual vaccine was less effective against this H1[SUB]av[/SUB]N2-HA 1C.2.4 than against H1[SUB]av[/SUB]N1-HA 1C.2.1, which may have contributed to the H1[SUB]av[/SUB]N2 epizootic and dissemination in pig farms in France.
Keywords: H1N2 subtype; Influenza virus; post-infection immunity; reassortant virus; swine; vaccination.
. 2024 May 21;55(1):65.
doi: 10.1186/s13567-024-01319-5. Pathogenicity and escape to pre-existing immunity of a new genotype of swine influenza H1N2 virus that emerged in France in 2020
Céline Deblanc[SUP] 1 [/SUP], Stéphane Quéguiner[SUP] 2 [/SUP], Stéphane Gorin[SUP] 2 [/SUP], Gautier Richard[SUP] 2 [/SUP], Angélique Moro[SUP] 3 [/SUP], Nicolas Barbier[SUP] 2 [/SUP], Gérald Le Diguerher[SUP] 3 [/SUP], Frédéric Paboeuf[SUP] 3 [/SUP], Séverine Hervé[SUP] 2 [/SUP], Gaëlle Simon[SUP] 2 [/SUP]
Affiliations
- PMID: 38773540
- DOI: 10.1186/s13567-024-01319-5
In 2020, a new genotype of swine H1N2 influenza virus (H1[SUB]av[/SUB]N2-HA 1C.2.4) was identified in France. It rapidly spread within the pig population and supplanted the previously predominant H1[SUB]av[/SUB]N1-HA 1C.2.1 virus. To characterize this new genotype which is genetically and antigenically distant from the other H1[SUB]av[/SUB]Nx viruses detected in France, an experimental study was conducted to compare the outcomes of H1[SUB]av[/SUB]N2 and H1[SUB]av[/SUB]N1 infections in pigs and evaluate the protection conferred by the only inactivated vaccine currently licensed in Europe containing an HA 1C (clade 1C.2.2) antigen. Infection with H1[SUB]av[/SUB]N2 induced stronger clinical signs and earlier shedding than H1[SUB]av[/SUB]N1. The neutralizing antibodies produced following H1[SUB]av[/SUB]N2 infection were unable to neutralize H1[SUB]av[/SUB]N1, and vice versa, whereas the cellular-mediated immunity cross-reacted. Vaccination slightly altered the impact of H1[SUB]av[/SUB]N2 infection at the clinical level, but did not prevent shedding of infectious virus particles. It induced a cellular-mediated immune response towards H1[SUB]av[/SUB]N2, but did not produce neutralizing antibodies against this virus. As in vaccinated animals, animals previously infected by H1[SUB]av[/SUB]N1 developed a cross-reacting cellular immune response but no neutralizing antibodies against H1[SUB]av[/SUB]N2. However, H1[SUB]av[/SUB]N1 pre-infection induced a better protection against the H1[SUB]av[/SUB]N2 infection than vaccination, probably due to higher levels of non-neutralizing antibodies and a mucosal immunity. Altogether, these results showed that the new H1[SUB]av[/SUB]N2 genotype induced a severe respiratory infection and that the actual vaccine was less effective against this H1[SUB]av[/SUB]N2-HA 1C.2.4 than against H1[SUB]av[/SUB]N1-HA 1C.2.1, which may have contributed to the H1[SUB]av[/SUB]N2 epizootic and dissemination in pig farms in France.
Keywords: H1N2 subtype; Influenza virus; post-infection immunity; reassortant virus; swine; vaccination.