Intranasal immunization with live recombinant Lactococcus lactis combined with heat-labile toxin B subunit protects chickens from highly pathogenic avian influenza H5N1 virus
Authors: Daxian Zhao
Xiaojue Peng
Handing Shu
Han Lei
Journal: Journal of Medical Virology (2015)
Discipline: MICROBIOLOGY
Keywords: H5N1 virus challenge; L. lactis‚Ä?‚ÄâLTB; intranasal immunization.
Affiliations: Department of Biotechnology, College of Life Science and Food Engineering, Nanchang University, Nanchang, Jiangxi, China.

Abstract:  Development of safe and effective vaccines to prevent highly pathogenic avian influenza H5N1 virus infection is a challenging goal. Lactococcus lactis (L. lactis) is an ideal delivery vector for vaccine development, and it has been shown previously that oral immunization of encapsulated secretory L. lactis-hemagglutinin (HA) could provide complete protection against homologous H5N1 virus challenge in the mice model. While intranasal immunization is an appealing approach, it is now reported that secretory L. lactis-HA combined with mucosal adjuvant heat-labile toxin B subunit (LTB) could provide protective immunity in the chicken model. As compared to intranasal immunization with L. lactis-HA alone, L. lactis-HA combined with LTB (L. lactis-HA + LTB) could elicit robust neutralizing antibody responses and mucosal IgA responses, as well as strong cellular immune responses in the vaccinated chickens. Importantly, intranasal immunization with L. lactis-HA + LTB could provide 100% protection against H5N1 virus challenge. Taken together, these results suggest that intranasal immunization with L. lactis-HA + LTB can be considered as an effective approach for preventing and controlling infection of H5N1 virus in poultry during an avian influenza A/H5N1 pandemic. 

Retracted: No

PubPeer comments:
 Brought to my attention by a reader. This paper is one of a set of six papers that all share the same authors, were all published in 2014-2015, and that all share very similar plots. No matter what animal species (mouse, chicken, or ferret) or number of animals per group (6-25), the body weight loss in unprotected animals was all very similar (around 25% loss at day 6), while the protected animals all show a dip in body weight around 6 days, followed by an increase. In addition, the error bars (standard deviations in all papers) are unexpectedly small for these types of measurements. Could the authors please provide some explanation for these similarities? The 6 papers are the following: * Han Lei et al. Virology 476 (2015) 189u2013195, DOI: 10.1016 j.virol.2014.12.017, https: pubpeer.com publications E932C6D86F69113141665259EB4C79 * Han Lei et al. Arch Virol (2015) 160:3011u20133019, DOI: 10.1007 s00705-015-2587-8, https: pubpeer.com publications 4E88CDED2683B085DE9D52B7AD7700 * Han Lei et al. BMC Veterinary Research (2015) 11:85, DOI: 10.1186 s12917-015-0399-4, https: pubpeer.com publications B407285D6C4C238DC25A4FA0F28991 * Han Lei et al. Virus Research 196 (2015) 56u201359, DOI: 10.1016 j.virusres.2014.11.009, https: pubpeer.com publications 889BA6B1AE96E94614521AA9583E87 * Han Lei et al. Microb Cell Fact (2015) 14:111, DOI: 10.1186 s12934-015-0287-4, https: pubpeer.com publications A13874959B0962999C5A01039B8D02 * Han Lei et al. Journal of Medical Virology (2014), DOI: 10.1002 jmv.23983, https: pubpeer.com publications BFBF1A36BD6B9C54611A9727DA0206 And here are the graphs:      ,