Figure 5. T cell mediated destruction of β- cells in diabetes type 1. CD4+ effector T cells recognize an insulin or islet peptide presented by diabetes-risk conferring HLA-DQ8 or DR4 on APCs, migrate to the pancreas and promote pancreatic β-cell destruction. Inside the pancreatic islets CD8+ effector T cells recognize islet antigens presented by HLA-A2 leading to the destruction of the β-cells. [Modified by Mitchel et al (87)]. TCR, T cell receptor; APC, antigen presenting cell; HLA-A2, human leukocyte antigen-A2.