Question

As a child, you greatly disliked having to receive vaccines by injection (shots). Therefore, you have elected to genetically engineer a vaccine that can be administered via ingestion. How would you design such a vaccine? (Provide concrete steps) What maybe some limitations of the vaccine you have designed? (example efficacy of the vaccine, effect of digestion).

Answer 1

The steps to be taken in order to design the oral vaccine can be found as below:

1. Isolate the primary gene sequence of the organism which causes virulence. This sequence will serve as the gene of interest.
2. Transfer this gene of interest into a vector which can express the sequence under a highly expressed promoter.
3. Transfer this gene vector into a suitable host which can over-express the gene.
4. Isolate the protein synthesized in the cells and perform concentration steps using simple techniques such as dialysis etc.
5. Immunize the host/subjects orally using this vaccine and observe for phenotypic effects.

Some of the limitations of the oral vaccines can be found as below:

1. The vaccine is actually a proteinceous molecule, hence it is subjected to degradation by the action of peptidase enzymes in the stomach.
2. Rapid digestion and breakdown of the proteinaceous candidate vaccine molecule is highly expected hence decreasing its therapeutic effects.
3. Multiple booster dosages are essentially required to obtain the desired phenotypic effects of the vaccine.
4. Such vaccines have lower shelf-life and require essential arrangements for storage such as low temeprature and humidity.