What does PRR mean in UNCLASSIFIED

Pattern Recognition Receptors (PRRs) are a group of proteins expressed by the innate immune system that recognize specific molecular patterns associated with pathogens or damage. These patterns are known as Pathogen-Associated Molecular Patterns (PAMPs) and Damage-Associated Molecular Patterns (DAMPs), respectively. PRRs play a crucial role in the initiation and regulation of immune responses against invading pathogens and tissue damage.

There are various types of PRRs, each recognizing different PAMPs or DAMPs. Some well-known classes of PRRs include:

• Toll-like receptors (TLRs)
• NOD-like receptors (NLRs)
• RIG-I-like receptors (RLRs)
• C-type lectin receptors (CLRs)
• Scavenger receptors (SRs) Each class of PRRs has distinct ligand specificity and signaling pathways, contributing to a diverse immune response.

PRRs recognize specific PAMPs or DAMPs through their ligand-binding domains. Upon binding, they undergo conformational changes that trigger intracellular signaling pathways. These pathways involve the activation of transcription factors and the production of pro-inflammatory cytokines and chemokines. PRRs can also induce phagocytosis and antigen presentation, facilitating the adaptive immune response.

PRRs play a fundamental role in the innate immune system's ability to detect and respond to pathogens and tissue damage. They initiate and regulate inflammatory responses, facilitating the recruitment of immune cells to the site of infection or injury. PRRs also contribute to immune tolerance by discriminating between self and non-self molecules, preventing excessive or inappropriate immune activation.

Aberrant PRR function has been implicated in various diseases, including autoimmune disorders, inflammatory diseases, and cancer. Dysregulated PRR signaling can lead to chronic inflammation, tissue damage, and impaired immune responses. Conversely, polymorphisms or defects in PRRs can result in immune deficiencies and increased susceptibility to infections.