Bacterial ​​component vaccine against American Foulbrood

This project aims to tackle two major bacterial infections that have significant economic impacts on beekeeping, namely American Foulbrood (AFB) and European Foulbrood (EFB). These infections affect the larval stages of honey bees, causing death in their pre-pupal or pupal life stages. AFB can strike both strong and weak hives, severely affecting hive health. EFB typically targets weakened hives and remains unnoticed until bees face additional stressors like adverse weather or poor nutrition.

There is no known cure for AFB, and treating EFB with antibiotics poses concerns of resistance and chemical residues in honey. Recent progress in AFB treatment involves the development of an oral "vaccine" that provides 30 to 50% protection to new bee larvae through Trans-generational Immune Priming (TGIP). TGIP is a feature of the invertebrate immune system that enhances resistance against previously encountered pathogens, passing this protection on to the next generation.

Although this advancement is promising, the effectiveness of TGIP in honey bees remains uncertain. Different factors such as exposure routes, genetic or epigenetic variations in the bees, and the type of pathogen can influence its success. For instance, while TGIP has shown moderate protection against AFB caused by P. larvae, it has not been effective against EFB caused by M. plutonius.

The project team propose developing an efficient single-shot vaccine using bacterial extracellular vesicles (BEVs) derived from P. larvae and M. plutonius to overcome these challenges. These BEVs contain a range of bioactive substances that will activate the honey bee immune system, providing a more potent and comprehensive defence than current priming vaccines.