While most people think that the immune system is there to protect us from pathogens, we know that you know better. For those more plugged into the science of immunology, you know that the immune system is there to identify self and non-self cells and molecules. Human immune systems can make generalized identifications of non-self things AND recognize specific non-self things. This brings us to the innate immune system and Toll-like receptors (TLR).
I Don’t Remember This
Unlike the adaptive immune system, the innate immune system has no memory. It won’t “remember” that a particular molecule has been inside the body. Its job is simply to recognize non-self things and get rid of them. These “things” can be as innocuous as pollen or dust floating around in the air or as dangerous as antibiotic-resistant bacteria that crawl into an open wound. Specific cells have membrane proteins stuck on the outside whose structure can bind to various types of non-self things – these proteins are called Toll-like receptors.
TLRs and Conservation
As life evolved on this planet, certain molecular structures were conserved. These are usually important structures and are atomically similar as you move from organism to organism. For example, DNA polymerase is highly conserved – its structure changes very little from species to species. This makes sense, right? After all, living things are made of cells, and cells contain DNA. An enzyme's job to partake in DNA replication wouldn’t change much over time.
Since You All Have This…
Toll-like receptors take advantage of these conserved structures in microbes. They bind to things like bacteria peptidoglycan (the cell wall in Gram+ bacteria) or lipopolysaccharides (found in Gram- bacteria). In total, there are 13 different types of TLRs that recognize various pathogens and antigens. Once a TLR binds to a non-self antigen, a series of complex signaling pathways are activated, and an immune response is launched.
Innate Immune Reponse
For you, dear human, this immune response feels like a runny nose, itchy skin, swelling, wheezing, narrowing of the airway, tightness in your chest, watery eyes, and other fun symptoms. If your body overreacts and launches a full-blown attack on some poor pollen, you experience this response as allergies. But if you cut yourself, this response is localized to the wound and helps prevent bacteria from entering your bloodstream. In the context of humans and our evolution, an innate immune system response triggered by activated TLRs is meant to protect us from everyday non-self things.
Generally Speak, TLRs Make Great Gifts
We find the intricate make up of the immune system fascinating, which is why we created the Toll-like receptor necklace. Like the function of TLRs, this necklace is a generalized structure of what TRLs look like. Who doesn’t love generalizing? This piece would make a great gift for immunologists, allergists, biochemists, and starry-eyed pre-med students.
written by Science with Evie