New research shows potential for vaccines to become even more effective, using toll-like receptor (TLR) agonists (activators) to get a stronger response from the immune system. The study, published in ACS Central Science, investigated the TLR agonist mechanism of directing the immune system, used to boost the effectiveness of antigen-based vaccines. Some vaccines, like the annual flu vaccine, recruit a dead or weakened virus to stimulate the innate immune system and activate TLRs. Antigen-based vaccines use only a small fragment of the virus to stimulate the immune system, and subsequently they achieve a smaller immune response - however with less side effects than whole pathogen vaccines.
TLRs are "first-responders" that play a large role in detecting infecting pathogens through pattern recognition, a process where both the innate and adaptive immune systems are activated to fight the infection (Nature). TLR activators are "common adjuvants" added to antigen-based vaccines in order to enhance their effectiveness. Dr. Aaron Esser-Kahn, lead researcher of the study, and his team looked to manipulate this mechanism to improve vaccines using the molecules TLR agonists use to activate the immune system.
Significant findings showed TLR agonist activity is impacted by their arrangment in space. Esser-Kahn and his team then looked to "probe this biological machinery" by displaying three different TLR agonists "with a defined spatial orientation" on synthesized probes. Rather than simply combining the three TLR agonists together to stimulate an immune response, the probe that spatially connected the activators raised a more effective immune response.
Moving forward, Esser-Kahn and his team will continue by breaking down the TLR agonists to see which specific actions each component performs and which actions are most important to activating an immune response.
Watch the following TLR animation to visualize how these "cellular watchmen" naturally stimulate the innate immune system during infection.
Source: ScienceDaily