2010
1. We can harness the immune system of ruminants to target growth of methanogens, and reduce production of methane
Our first breakthrough showed the immune system of sheep can generate antibodies that bind to methanogens, which are the methane producing microbes.
When added to cultures of a rumen methanogen, the antibodies caused cell clumping (agglutination), and slowed methanogen growth and methane production.
2. Genomics used to identify antigenic targets on the methanogen cells
We wanted to know what targets on the surface of the methanogens could be used to vaccinate sheep to make antibodies.
In a world first study, we sequenced the first genome of a rumen dwelling methanogen, and found that there were potential vaccine targets.
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0008926
2013-2014
3. Antibodies produced by vaccination are long-lived and can be boosted
A methane vaccine needs to generate an antibody response that is maintained long after injection, if it is to have a lasting impact and to be cost effective.
We found that antibodies to methanogen antigens persisted in the blood and saliva of vaccinated animals for at least six months and levels can be boosted after a single re-vaccination.
Reported in a presentation at GGAA 2013, Dublin, Ireland
4. Protein and peptide antigens generate antibodies in vaccinated sheep and cattle
Vaccine antigens identified in the genome of Methanobrevibacter ruminantium were produced as recombinant proteins and synthetic peptides.
Sheep and cattle vaccinated with these produced strong immune responses, necessary for an effective vaccine.
https://www.sciencedirect.com/science/article/abs/pii/S0165242715000513
2015-2016
5. Demonstrating that methanogen populations in the rumen are similar worldwide
We initiated a study a project with 140 scientists from 73 organisations to conduct a census of rumen microbes.
This showed that the same rumen methanogens dominate the microbiome regardless of ruminant species, diet or geographic location.
6. Vaccination produces enough antibodies in saliva to coat all methanogens in the rumen
Vaccination generates specific antibodies in the sheep saliva and sheep are estimated to swallow up to 15 litres of saliva every day.
When the sheep swallow saliva, the antibodies enter the rumen – and there are enough of them to cover the surface of the methanogen microbes – more than 10,000 antibody molecules per methanogen cell.
7. Antibodies can stay active in the rumen for several hours – long enough to be effective
After vaccination, the antibodies from saliva that end up in the rumen can stay active for several hours before breaking down. This is long enough for them to be effective.
https://www.sciencedirect.com/science/article/abs/pii/S0165242715000513
2020
8. Showed that induced antibodies bound to their specific methanogen protein targets
We showed that vaccine antigens can induce antibodies that bind to their intended target proteins.
This is required for targeted antibody production to selected methanogen antigens in the rumen.
2022
9. Demonstrated that methanogens have antigens in common
We demonstrated that there is cross-reactivity between diverse strains of rumen methanogens.
This is important for a commercial vaccine in which few antigens will need to target large parts of the methanogen diversity.
Link to:
https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.918111/full
10. Showed how to identify responsive vaccine epitopes for vaccine design
We showed that antibodies can bind to specific parts of a protein target.
This means we can direct the antibody response to key targets on the surface of rumen methanogens.
