What is the difference between T cell receptors and MHC molecules?
T cell receptors are proteins that are expressed on the surface of T cells. They are responsible for recognizing antigens, which are fragments of foreign proteins. When a TCR binds to an antigen, it triggers the T cell to become activated.
MHC molecules (also known as human leukocyte antigen molecules) are proteins that are expressed on the surface of all cells in the body. They present antigens to T cells. When a TCR binds to an antigen that is presented by an MHC molecule, it triggers the T cell to become activated.
The main difference between TCRs and MHC molecules is their function. TCRs are responsible for recognizing antigens, while MHC molecules are responsible for presenting antigens. However, both TCRs and MHC molecules are essential for the adaptive immune system to function properly.
Here is a table that summarizes the key differences between TCRs and MHC molecules:
| Feature | TCR | MHC molecule |
|---|---|---|
| Function | Recognizes antigens | Presents antigens |
| Location | Surface of T cells | Surface of all cells in the body |
| Structure | Protein | Protein |
| Role in adaptive immune system | Activates T cells | Presents antigens to T cells |
TCRs and MHC molecules are both essential components of the adaptive immune system. They work together to identify and destroy foreign invaders.