Abstract
Characterization of multiple antibody epitopes has revealed the necessity of specific groups of amino acid residues for reactivity. This applies to the majority of antibody–antigen interactions, where especially charged and hydrophilic amino acids have been reported to be essential for antibody reactivity. This study describes thorough characterization of glutamic acid decarboxylase (GAD) 65 antigenic epitopes, an immunodominant autoantigen in type 1 diabetes (T1D). As linear epitopes are sparsely described for GAD65 in T1D, we aimed to identify and thoroughly characterize two GAD65 antibodies using immunoassays. A monoclonal antibody recognized an epitope in the N-terminal domain of GAD65, 8FWSFGSE14, whereas a polyclonal antibody recognized two continuous epitopes in the C-terminal domain, corresponding to amino acids 514RTLED518 and 549PLGDKVNF556. Hydrophobic amino acids were essential for antibody reactivity, which was verified by competitive inhibition assays. Moreover, the epitopes were located in flexible linker regions and turn structures. These findings confirm the versatile nature of antibody–antigen interactions and describe potential continuous epitopes related to T1D, which predominantly have been proposed to be of discontinuous nature.
Highlights
The majority of epitopes currently analyzed are discontinuous [1]
This applies to the majority of antibody–antigen interactions, where especially charged and hydrophilic amino acids have been reported to be essential for antibody reactivity
As linear epitopes are sparsely described for GAD65 in type 1 diabetes (T1D), we aimed to identify and thoroughly characterize two GAD65 antibodies using immunoassays
Summary
The majority of epitopes currently analyzed are discontinuous [1]. As the epitopes are composed of similar amino acids (aas), results obtained using continuous epitopes are directly related to discontinuous models. The majority of epitopes are composed of 8–12 aas [1,2,3,4,5,6]. Secondary structures and structure flexibility are central elements for a stable antibody-antigen interaction. Loops and turns, and occasionally α-helices favored epitope structures [1,10,11,12,13]. Epitopes primarily located on the surface of proteins are often favored due to an increased antibody accessibility [1,4]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
