Pattern recognition receptors: sentinels in innate immunity and targets of new vaccine adjuvants

Abstract

The innate immune system plays an essential role in the host’s first line of defense against microbial invasion, and involves the recognition of distinct pathogen-associated molecular patterns by pattern recognition receptors (PRRs). Activation of PRRs triggers cell signaling leading to the production of proinflammatory cytokines, chemokines and Type 1 interferons, and the induction of antimicrobial and inflammatory responses. These innate responses are also responsible for instructing the development of an appropriate pathogen-specific adaptive immune response. In this review, the focus is on different classes of PRRs that have been identified, including Toll-like receptors, nucleotide-binding oligomerization domain-like receptors, and the retinoic acid-inducible gene-I-like receptors, and their importance in host defense against infection. The role of PRR cooperation in generating optimal immune responses required for protective immunity and the potential of targeting PRRs in the development of a new generation of vaccine adjuvants is also discussed.

Keywords::

• host defense
• inflammasome
• innate immunity
• nucleotide-binding oligomerization domain-like receptor
• pattern recognition receptor
• retinoic acid-inducible gene-I-like receptor
• Toll-like receptor
• vaccine adjuvant

Acknowledgements

The author gives special thanks to Madeleine Flynn (QIMR) who has worked with her on the illustrations presented in this review.

Financial & competing interests disclosure

This work was supported by the National Health and Medical Research Council of Australia. The author has no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.