TCR

Definition

TCR (T Cell Receptor) is a molecule found on the surface of T lymphocytes that is responsible for recognizing antigens bound to major histocompatibility complex (MHC) molecules. It plays a crucial role in the adaptive immune response by helping T cells identify and respond to specific pathogens.

5 Must Know Facts For Your Next Test

1. TCRs are composed of two different polypeptide chains, usually referred to as alpha (α) and beta (β).
2. The antigen-binding site of a TCR is highly variable, allowing for the recognition of a wide range of antigens.
3. TCRs recognize peptide fragments of antigens that are presented on the surface of cells by MHC molecules.
4. Activation of T cells through TCR binding requires additional co-stimulatory signals provided by other molecules on the antigen-presenting cell.
5. There are two main types of TCRs: αβ TCRs and γδ TCRs, with αβ TCRs being more common in human peripheral blood.

Review Questions

Related terms

Antigen-Presenting Cell (APC): A cell that displays foreign antigens complexed with MHC on its surface to activate T cells.

Major Histocompatibility Complex (MHC):

A set of cell surface proteins essential for acquired immune system to recognize foreign molecules.

Co-Stimulatory Signal: Additional signal required along with antigen recognition for full activation of naive T cells.