Toll-like receptor agonists: a patent review (2011 - 2013).
BACKGROUND
Toll-like receptors (TLRs) are a crucial part of the innate immunity and present the first line of defense against pathogens. In humans, there are ten TLRs, with TLR3, 7, 8 and 9 located in intracellular vesicles and the remaining expressed on the cell surface. These transmembrane protein receptors recognize a wide range of pathogen components. A large number of TLR agonists, either derived from pathogen components or modified synthetic molecules, were developed and investigated for their ability to stimulate an immune response.


METHODS
This review includes an updated summary (2011 - 2013) of TLR agonists that have been published in patent applications and/or progressed to clinical studies, with an emphasis on their chemical structure, immune response, prophylactic and therapeutic outcomes.


CONCLUSIONS
A number of factors have contributed to the design and development of TLR agonists such as solving the crystal structures of TLR bound to their ligands, improvements in our understanding of the signaling pathway activated after TLR stimulation and the identification of the native ligands of all human TLRs. Some of the TLR agonists have been approved for human use by the FDA while others have reached clinical studies in Phases I, II and III. Generally, immunotherapy based on TLR agonists is very promising for the prevention and/or treatment of several disorders including cancer, allergy and microbial infections. However, many TLR agonists were withdrawn from further studies as they either lacked efficacy or caused serious side effects.
The University of Queensland, School of Chemistry and Molecular Biosciences , St. Lucia, Brisbane, Qld 4072 , Australia.
Waleed M
WM
Hussein
Tzu-Yu
TY
Liu
Mariusz
M
Skwarczynski
Istvan
I
Toth
D000818:Animals; D055808:Drug Discovery; D006801:Humans; D010330:Patents as Topic; D015398:Signal Transduction / Q000502:physiology; D051193:Toll-Like Receptors / Q000819:agonists*
D051193:Toll-Like Receptors