Developing targeting strategies for mucosal-administered inactivated vaccines applicable to livestock animals.

Why is this challenge important?

Livestock animals (poultry, swine, ruminants) are commonly receiving (live) vaccines that are administered via the mucosal route (drinking water or feed for oral route or spray into respiratory system).

The main advantage of mucosal-applied vaccines is that they can be mass-applied and are convenient for the customer and the animal (no stress due to injection or impact on performance). In general, live vaccines still bear safety risks (too ‘hot’, potential risk of return to virulence). For that reason, inactivated vaccines that are applicable for mucosal administration are of high interest to be developed for livestock animals.

However, within the mucosal tract there are only a limited number of cellular entry portals available where antigenic material can be actively taken up for processing. This is exerted by the so-called Microfold (M-) cells that are specialized epithelial cells covering the underlying lymphoid tissue and have the capacity to a-specifically sample antigen from the luminal area for processing and subsequently presentation towards the underlying immune cells. The local mucosal conditions are however harsh that urge the development of vaccine formulations ensuring antigen stability under variable pH and the presence of proteolytic enzymes. As an additional layer of complexity, the mucosal immune system is skewed towards a tolerogenic state that requires sufficient immunogenicity of a vaccine formulation for the induction of a response.
Together, this emphasizes that targeted delivery to these gatekeeper cells by improved vaccine formulations and/or delivery technologies are key in order to develop an efficacious mucosal inactivated vaccine.

For this challenge, we are looking towards novel approaches that may enable targeted delivery of vaccine antigens towards mucosal M-cells.

Novel and innovative ideas that could support the feasibility research towards efficacious inactivated vaccines for oral administration.