A research team at the University of Würzburg is testing a novel approach for a vaccine against the coronavirus - for swallowing. The advantages: Comparatively cheap to produce, easy to administer and relatively stable even at normal temperatures.
If Prof. Thomas Rudel from the Julius Maximilians University of Würzburg and the biopharmaceutical company Aeterna Zentaris in Frankfurt have their way, there could possibly be significant reinforcements in the fight against the global corona pandemic in the future: a vaccination that does not come with the syringe rather than as a capsule that can easily be swallowed. Preclinical development has already started.
Thomas Rudel holds the chair for microbiology at the Julius Maximilians University of Würzburg (JMU) and had the idea for oral vaccination a good year ago Typhoid infection is at work ". The oral typhoid vaccine is based on a special strain of bacteria, Salmonella Typhi Ty21a.
Rudel and the scientists in his laboratory are now also working with this bacterial strain - with a significant modification: "We have programmed the bacteria to produce SARS-CoV-2 antigens," explains the microbiologist. Rudel was supported by the microbiologist Dr. Birgit Bergmann. Protected from gastric acid attack in a capsule, the bacteria are supposed to develop their effect in the human small intestine after passing through the stomach. The scientific approach assumes that the bacteria can present the antigens to the immune system there.
"Special cells in the intestinal wall are supposed to ensure that bacteria and the antigens are absorbed by immune cells and transported further into lymphoid tissue," says Rudel. There they could in turn activate other cells of the immune system - so-called B and T cells - and set an immune response in motion. Rudel hopes that, if successful, this immune response will be so strong that all human mucous membranes will be put on alert and, as a result, coronaviruses will be prevented from entering the body there.
The advantages are obvious
In order to remain effective against newly emerging virus mutations, Rudel's team developed the bacteria in such a way that they produce not one, but two antigens at the same time. So if one antigen is only weakly effective due to a virus change, the second antigen could serve as a “safety anchor”: It is based on a gene that has been shown to mutate only rarely.
The vaccine from the Franconian laboratory would also have several advantages: It would be cheap to manufacture, easy to administer and relatively stable even at normal temperatures.
Optimistic as well as realistic
The development of the vaccine strains and the preclinical work is financially supported by Aeterna Zentaris GmbH. The pharmaceutical company would undertake the subsequent clinical tests. Rudel is confident that the necessary permits could be obtained relatively quickly. A few years ago, Aeterna Zentaris had been working with a similar process on a vaccine against prostate cancer, which was about to start clinical trials and had been officially approved for clinical examination. The team can now build on these experiences.
Nevertheless, Rudel is cautiously optimistic. There is no guarantee thbat an oral vaccination against Covid-19 will soon be available in pharmacies, warns Rudel. After all, many active ingredients have failed even at a late stage of development because they were not sufficiently effective or had unexpected and undesirable effects.
