Immunostimulants in animals: mechanisms of action

Immunostimulants can work by presenting a pathogen-associated molecular pattern that is recognized by toll-like receptors, or TLRs, in innate immune cells, triggering an immune response. Cytokines, the signaling molecules of the immune system, can also be administered to activate an immune response. A further way of modulating the immune system is to change the activity of downstream components of the TLR signaling pathway.

Potential immunostimulators that have been investigated include bacterial cell wall components, modified viruses, small DNA sequences that mimic bacterial DNA, and cytokines.