GAD65 (524-543) is a biologically active peptide comprising amino acids 524 to 543 of glutamic acid decarboxylase 65 (GAD65). It represents an early islet antigen fragment that elicits proliferative T cell responses in the non-obese diabetic (NOD) mouse model, instrumental in spontaneous autoimmune diabetes research. The peptide serves as a specific, possibly low affinity stimulant for the diabetogenic T cell clone BDC2.5. Notably, immunization with GAD65 (524-543) heightens NOD mice's vulnerability to type 1 diabetes when subjected to the adoptive transfer of BDC2.5 T cells.

GAD65 (206-220) is a synthetic peptide derived from glutamic acid decarboxylase (GAD) 65, specifically corresponding to residues 180-188. It is known that GAD65 interacts with I-Ag7 MHC class II molecules and is a significant pancreatic antigen that self-reactive T cells target in type I diabetes mellitus.

GAD65(247-266) epitope TFA, a T cell epitope derived from islet antigens, exhibits competitive binding to the type I diabetes-associated molecule I-A g7, albeit with low affinity. This epitope corresponds to a sequence within Glutamic Acid Decarboxylase 65, an enzyme implicated in the transformation of glutamate into gamma-aminobutyric acid (GABA) [1].