Novel Vaccine Adjuvant with Potent Immunostimulatory Properties

Researchers from JCU have discovered particles in the well-known “superfood” spirulina that may significantly improve the efficacy and production of vaccines.

Under the direction of Dr. Farouq Sharifpour, DVM, PhD, of JCU's Australian Institute of Tropical Health & Medicine (AITHM), the study explores the potential therapeutic advantages of Spirulina extracellular vesicles (SPEV).

Dr. Sharifpour and his team discovered that SPEV has enormous potential as a novel class of vaccine adjuvant (substances added to vaccines to make them more effective) while conducting safe testing on mice.

We were working on spirulina on a totally different project, but when we realized that nobody has previously worked on extracellular vesicles, or reported on extracellular vesicle isolation from spirulina, we jumped at that chance. We injected them directly into mice, and we found instantaneous pro-inflammatory effects, meaning that they boost inflammation. This was not the sort of inflammation that harms you, it is an inflammation without any adverse effect."

Dr. Farouq Sharifpour, Study Lead, James Cook University

Sharifpour said, “Through several exposures, several injections to mice, it still had this pro-inflammatory effect and from there we thought if elevates immunities, and if it boosts immune response without any adverse effects, why not we use it as a vaccine adjuvant?”

Humans have been consuming spirulina for thousands of years, and more recent research has shown that these cyanobacteria can help with a variety of chronic illnesses, such as diabetes, obesity, cancer, and intestinal health.

Dr. Sharifpour and his team isolated and identified SPEVs and their particular proteins using a variety of methods, such as transmission electron cryomicroscopy, which studies samples at cryogenic temperatures.

“We injected the mice with these antigenic proteins, with this vaccine antigen and we realized that compared to when you inject this vaccine antigen alone, the Spirulina elevates the immune response to that specific protein by around 1000-fold,” Sharifpour said.

It was certainly surprising and it is very much comparable to chemical adjuvants that are used in the vaccine industry today, which generally have some adverse effects. We did not see any adverse effects in the mice, and we are hoping that SPEVs can be used in the next generation of adjuvants. However, more experiments are needed to be done."

Dr. Farouq Sharifpour, Study Lead, James Cook University

Using a method known as mass spectrometry, Dr. Sharifpour and his colleagues extracted proteins and tried to determine which ones were in charge of which immunological effects.

Additionally, Spirulina has been genetically modified to express non-native proteins by the lead author, Dr. Sharifpour.

He thinks that self-adjuvating vaccines made from genetically modified spirulina EVs could do away with the need to produce vaccines and adjuvants separately.

With the potential advantages of affordability and scalability, genetically engineering spirulina to produce vaccine antigens and EVs is an economical vaccine production method.

Since spirulina is very, very affordable in culture, you can have a large scale of spirulina at a fraction of the of the cost of other subunit vaccines that we have today. It could potentially lead to a paradigm shift in the vaccine industry. We can produce farms of genetically engineered spirulina so that they produce this vaccine antigen, and we can harvest EVs from them and then inject it into individuals to make it more affordable.”

Dr. Farouq Sharifpour, Study Lead, James Cook University