Presenting Influenza A M2e Antigen on Recombinant Spores of Bacillus subtilis
Tomasz Łęga1, Paulina Weiher2, Michał Obuchowski3
1Department of Medical Biotechnology, Intercollegiate Faculty of Biotechnology, University of Gdańsk and Medical University of Gdańsk, Gdańsk, Poland.
Abstract:
Effective vaccination against influenza virus infection is a serious problem mainly due to antigenic variability of the virus. Among many of investigated antigens, the extracellular domain of the M2 protein (M2e) features high homology in all strains of influenza A viruses and antibodies against M2e and is protective in animal models; this makes it a potential candidate for generation of a universal influenza vaccine. However, due to the low immunogenicity of the M2e, formulation of a vaccine based on this antigen requires some modification to induce effective immune responses. In this work we evaluated the possible use of Bacillus subtilis spores as a carrier of the Influenza A M2e antigen in mucosal vaccination. A tandem repeat of 4 consensus sequences coding for human-avian-swine-human M2e (M2eH-A-S-H) peptide was fused to spore coat proteins and stably exposed on the spore surface, as demonstrated by the immunostaining of intact, recombinant spores. Oral immunization of mice with recombinant endospores carrying M2eH-A-S-H elicited specific antibody production without the addition of adjuvants. Bacillus subtilis endospores can serve as influenza antigen carriers. Recombinant spores constructed in this work showed low immunogenicity although were able to induce antibody production. The System of influenza antigen administration presented in this work is attractive mainly due to the omitting time-consuming and cost-intensive immunogen production and purification. Therefore modification should be made to increase the immunogenicity of the presented system.
Insights
Bacillus subtilis spores carrying the influenza M2e antigen show potential for universal vaccines. Oral vaccination in mice produced antibodies, offering a simpler production method but requiring enhanced immunogenicity.
Area of Science:
- Microbiology
- Immunology
- Vaccine Development
Background:
- Influenza virus's antigenic variability necessitates universal vaccine strategies.
- The M2 extracellular domain (M2e) is a conserved target for universal influenza vaccines.
- M2e's low immunogenicity requires formulation improvements for effective vaccines.
Purpose of the Study:
- To evaluate Bacillus subtilis spores as a mucosal vaccine carrier for the influenza A M2e antigen.
- To develop a simplified antigen production and purification system for influenza vaccines.
Main Methods:
- A tandem repeat of M2e consensus sequences (M2eH-A-S-H) was fused to Bacillus subtilis spore coat proteins.
- Recombinant spores displaying M2eH-A-S-H on their surface were generated and confirmed via immunostaining.
- Mice were orally immunized with recombinant M2eH-A-S-H spores to assess antibody production.
Main Results:
- Recombinant Bacillus subtilis spores successfully displayed the M2eH-A-S-H antigen on their surface.
- Oral immunization with M2eH-A-S-H spores induced specific antibody production in mice without adjuvants.
- The system simplified antigen administration, bypassing time-consuming production and purification.
Conclusions:
- Bacillus subtilis endospores can effectively serve as carriers for influenza antigens in mucosal vaccines.
- The M2e-displaying spores demonstrate potential for a universal influenza vaccine, though immunogenicity needs enhancement.
- This approach offers an attractive alternative to conventional vaccine production methods.
