More emerging viruses require an improved vaccine. Not everyone should receive every vaccine, due to individual differences in one's immune system. Fortunately, what French veterinarian Gaston Ramon discovered 1920s, left a lasting impact on how vaccines work.
According to him, certain additives could improve the immune response of vaccines. By experimenting with simple household items like breadcrumbs and oil, he laid down the foundation for what we call adjuvants today. Adjuvants have, in a century, become high-tech tools with the advancement of nanotechnology.
Vaccines and Adjuvants Mechanism
In August, Ben Ou and his colleague researchers from Stanford University published a study about the brand-new nanoparticle technology that can integrate both sorts of adjuvants.
Vaccines work by inducing the immune system to learn to see and fight against possible threats. They expose the body to antigens, which are harmless bits of pathogens, and initiate an immune response. For example, a COVID-19 vaccine uses the spike protein of the SARS-CoV-2 virus to induce immunity.
The immune response of the body has two phases: immediate response and delayed response:
- Immediate Response: Brief side effects like fever or soreness develop due to the inflammation created by cytokines.
- Long-term immunity: Antigens move to lymph nodes where immune cells, T cells, and B cells produce memory cells and antibodies.
Adjuvants amplify these responses, making the immunity rapid and long-lasting.
Accidental Findings: Origins of Adjuvant Science
Ramon's preliminary studies indicated that infections at vaccination sites provoked more potent immune reactions. At the same time, British immunologist Alexander Glenny discovered in England that aluminum salts induced immune responses. Since then, aluminum-based adjuvants have been the gold standard of vaccine development.
Nanotechnology: Transforming Adjuvant Design
Modern nanotechnology is recasting the design of adjuvants to provide unprecedented control over immune reactions. Nanoparticles provide scientists with the ability to control vaccine delivery and increase effectiveness.
The mRNA Covid-19 vaccines were exemplary breakthroughs, incorporating lipid nanoparticles as protective carriers of the fragile mRNA molecules to ensure that mRNA arrived intact at their target.
Researchers have made nanoparticle cages from immune-stimulating saponins and toll-like receptor (TLR) agonists for the latest research. TLRs are the front-runners in the immune system, where they recognize pathogens and initiate diverse immune responses.
Better Immunological Responses through Nanoparticle Adjuvants
Testing these nanoparticle adjuvants in COVID-19 and HIV vaccines elicited significantly stronger and longer-lasting immune responses than traditional aluminum-based adjuvants.
The scientists also tested various combinations of TLR agonists and saponin cages to modulate immune responses for specific needs.
Tailor-made Vaccines for Specific Immunity Age Groups
One of the most promising aspects of this dual-adjuvant system is its adaptability. As human immune systems evolve with age, vaccines can be fine-tuned to provide optimal protection for specific age groups or health conditions.
While clinical trials in humans are still some time away, the applications of this technology are numerous. From enhanced protection against emerging diseases to tailor-made vaccines for vulnerable populations, nanotechnology is set to hasten vaccine development—more effectively and better.
After all, long-lasting immunity against a certain disease is what humans need. But in the case of more virulent disease, a stronger vaccine should be used.
