Improved Stability Of Live, Attenuated Vaccine gdhA Derivative Pasteurella Multocida B:2 By Freeze Drying Technique

Background: Avian Pasteurella multocida is one of the pathogens that affect the health of poultry. The protective efficacy of traditional attenuated vaccine is not ideal. In previous study, we prepared ptfA gene DNA vaccine of avian P. multocida. However, the protective effect of ptfA gene DNA vaccine was inferior to the attenuated vaccine. Therefore, it is necessary to improve the immune efficacy of avian P. multocida DNA vaccine, such as screening for novel adjuvant. Methods: In this study, the peony seed proteolysis product was gavaged to chickens before DNA vaccination or was added to the ptfA gene DNA vaccine as adjuvant. These vaccines were administered to chickens and the serum antibody, lymphocyte proliferation levels, IFN-g, IL-2, IL-4 and IL-6 concentrations secreted by peripheral blood lymphocytes were determined. After challenging with virulent avian P. multocida, survival time and protective efficacy was evaluated. Result: Following vaccination, no significant differences in antibody levels and concentrations of IL-4 among the DNA vaccine group, adjuvant-DNA vaccine group and gavaged group were observed. The stimulation index (SI) values, concentrations of IFN-g, IL-2 and IL-6 in adjuvant-DNA vaccine group and gavaged group were significantly higher than those in the DNA vaccine group. The protective efficacy of live attenuated vaccine group, DNA vaccine group, adjuvant-DNA vaccine group and gavaged group were 92%, 52%, 72% and 60%, respectively. This study has laid a foundation for the design and application of future DNA vaccines of P. multocida and DNA vaccine adjuvant.

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Immunogenicity and Protective Efficacy of an Intranasal Live-attenuated Vaccine Against SARS-CoV-2

iScience ◽

10.1016/j.isci.2021.102941 ◽

2021 ◽

pp. 102941

Author(s):

Jun-Guy Park ◽

Fatai S. Oladunni ◽

Mohammed A. Rohaim ◽

Jayde Whittingham-Dowd ◽

James Tollitt ◽

...

Keyword(s):

Protective Efficacy ◽

Live Attenuated Vaccine ◽

Attenuated Vaccine

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A Live-Attenuated Prime, Inactivated Boost Vaccination Strategy with Chimeric Hemagglutinin-Based Universal Influenza Virus Vaccines Provides Protection in Ferrets: A Confirmatory Study

Vaccines ◽

10.3390/vaccines6030047 ◽

2018 ◽

Vol 6 (3) ◽

pp. 47 ◽

Cited By ~ 15

Author(s):

Raffael Nachbagauer ◽

Florian Krammer ◽

Randy Albrecht

Keyword(s):

Influenza Virus ◽

Respiratory Tract ◽

Virus Vaccine ◽

Influenza Viruses ◽

Inactivated Vaccine ◽

Upper Respiratory Tract ◽

Live Attenuated Vaccine ◽

Virus Surface ◽

Virus Challenge ◽

Attenuated Vaccine

Influenza viruses cause severe diseases and mortality in humans on an annual basis. The current influenza virus vaccines can confer protection when they are well-matched with the circulating strains. However, due to constant changes of the virus surface glycoproteins, the vaccine efficacy can drop substantially in some seasons. In addition, the current seasonal influenza virus vaccines do not protect from avian influenza viruses of human pandemic potential. Novel influenza virus vaccines that aim to elicit antibodies against conserved epitopes like the hemagglutinin stalk could not only reduce the burden of drifted seasonal viruses but potentially also protect humans from infection with zoonotic and emerging pandemic influenza viruses. In this paper, we generated influenza virus vaccine constructs that express chimeric hemagglutinins consisting of exotic, avian head domains and a consistent stalk domain of a seasonal virus. Using such viruses in a sequential immunization regimen can redirect the immune response towards conserved epitopes. In this study, male ferrets received a live-attenuated vaccine virus based on the A/Ann Arbor/6/60 strain expressing a chimeric H8/1 (cH8/1) hemagglutinin, which was followed by a heterologous booster vaccination with a cH5/1N1 formalin inactivated non-adjuvanted whole virus. This group was compared to a second group that received a cH8/1N1 inactivated vaccine followed by a cH5/1N1 inactivated vaccine. Both groups showed a reduction in viral titers in the upper respiratory tract after the A(H1N1)pdm09 virus challenge. Animals that received the live-attenuated vaccine had low or undetectable titers in the lower respiratory tract. The results support the further development of chimeric hemagglutinin-based vaccination strategies. The outcome of this study confirms and corroborates findings from female ferrets primed with a A/Leningrad/134/17/57-based live attenuated cH8/1N1 vaccine followed by vaccination with an AS03-adjuvanted cH5/1N1 split virus vaccine 10.

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