epitope
Chapter: 4
An epitope is a short, linear peptide sequence that is a portion of a larger protein antigen. Antigen-presenting cells (APC) process antigens and degrade them into short peptide sequences (epitopes), which are then expressed on the surface of the APC cell in association with Class I MHC molecules. This macromolecular complex (aggretope) is then recognized by specific helper T-cells, which can activate specific B-cells to respond to that epitope from that particular antigen. Thus, specificity of the immune response is maintained.