termsTerm
Epitope
aka epitopes, binding site, binding sites, binding domain, binding domains
The exact small patch on an antigen that an antibody or T cell actually grips, like the specific spot on a door handle a hand grabs. Two antibodies can bind the same protein at different epitopes.
An epitope is typically a cluster of five to fifteen amino acids on the surface of a protein. Trastuzumab and pertuzumab both bind HER2 but at different epitopes, which is why they can be given together, and zanidatamab is a single antibody built to grab both spots at once. For T cells, the epitope is a short peptide fragment held in an HLA molecule on the cell surface; a mutation that changes or removes the epitope lets a tumour cell slip past an antibody or T cell without changing anything else.
Category
Biology basics