Pattern Recognition Receptors

Definition

Pattern recognition receptors (PRRs) are a class of proteins expressed by cells of the innate immune system that play a crucial role in recognizing and responding to pathogens, including viruses. These receptors identify molecular patterns associated with microbial infections, such as viral RNA or specific proteins, leading to the activation of immune responses that help protect the host from viral infections.

5 Must Know Facts For Your Next Test

1. PRRs include various receptor families such as Toll-like receptors (TLRs), RIG-I-like receptors (RLRs), and NOD-like receptors (NLRs), each recognizing different types of viral components.
2. The activation of PRRs leads to the production of pro-inflammatory cytokines, enhancing the immune response and promoting the recruitment of immune cells to the site of infection.
3. PRRs not only detect viral infections but also help distinguish between self and non-self molecules, which is critical for preventing autoimmune responses.
4. The signaling pathways activated by PRRs can lead to the maturation of dendritic cells, linking the innate and adaptive immune systems by promoting T cell activation.
5. Some viruses have evolved mechanisms to evade detection by PRRs, which is a significant aspect of their immune evasion strategies.

Review Questions

• How do pattern recognition receptors initiate an immune response upon detecting viral infections?
  • Pattern recognition receptors initiate an immune response by recognizing specific molecular patterns associated with viruses, such as viral RNA or surface proteins. When these patterns are detected, PRRs activate signaling pathways that lead to the expression of pro-inflammatory cytokines. This cytokine release helps recruit other immune cells to the site of infection and enhances overall immune activity, providing a robust initial defense against the virus.
• Discuss the relationship between pattern recognition receptors and adaptive immunity.
  • Pattern recognition receptors play a critical role in bridging innate immunity and adaptive immunity. When PRRs recognize viral components, they not only trigger immediate inflammatory responses but also facilitate the maturation of antigen-presenting cells. These cells then present processed viral antigens to T cells, promoting their activation and differentiation into effector cells that specifically target and eliminate infected cells.
• Evaluate the impact of viral evasion strategies on the function of pattern recognition receptors in host immunity.
  • Viral evasion strategies significantly impact the function of pattern recognition receptors by employing various mechanisms to avoid detection. Some viruses may modify or hide their viral components so they are not recognized by PRRs, while others might produce proteins that interfere with PRR signaling pathways. This evasion undermines the host's immune response, allowing viruses to persist and replicate within the host, ultimately leading to more severe infections and challenges in treatment.

Related terms

Toll-like Receptors: A type of PRR that detects specific pathogen-associated molecular patterns (PAMPs) and initiates signaling pathways to trigger immune responses.

Cytokines: Signaling molecules produced by immune cells that mediate and regulate immunity, inflammation, and hematopoiesis in response to infections.

Antigen Presenting Cells: Cells that process and present antigens to T cells, playing a key role in the adaptive immune response after initial recognition by PRRs.