TolllikeRezeptor

Toll-like receptors, often abbreviated as TLRs, are a class of proteins that play a fundamental role in the innate immune system. They are found on the surface of various immune cells, such as macrophages and dendritic cells, as well as on epithelial cells. TLRs act as pattern recognition receptors, meaning they are able to detect specific molecular structures that are commonly found on pathogens but not on host cells. These microbial structures are known as pathogen-associated molecular patterns, or PAMPs. Examples of PAMPs include bacterial lipopolysaccharide (LPS), flagellin, and viral RNA.

When a TLR binds to its specific PAMP, it triggers a signaling cascade within the cell. This cascade leads to the activation of transcription factors, which in turn promote the expression of genes involved in the immune response. These genes encode for cytokines, chemokines, and other molecules that help to recruit immune cells to the site of infection, promote inflammation, and activate other components of the immune system. This initial response is crucial for controlling infections and initiating the adaptive immune response.

There are several different types of TLRs, each recognizing a distinct set of PAMPs. This specificity allows the immune system to mount an appropriate response to different types of pathogens. For instance, TLR4 is known to recognize LPS from Gram-negative bacteria, while TLR3 recognizes double-stranded RNA, a common feature of viral infections. The study of TLRs has significantly advanced our understanding of how the innate immune system detects and responds to threats, and has opened up avenues for therapeutic interventions in infectious diseases and inflammatory conditions.