TY - JOUR
T1 - A subclass of serum anti-ZnT8 antibodies directed to the surface of live pancreatic β-cells
AU - Merriman, Chengfeng
AU - Huang, Qiong
AU - Gu, Wei
AU - Yu, Liping
AU - Fu, Dax
N1 - Funding Information:
Acknowledgments—We thank Dr. Hao Zhang from the Flow Cytometry and Immunology Core Facility at Johns Hopkins Bloomberg School of Public Health for assistance in flow cytometry data acquisition and analysis. The Zeiss confocal microscope was supported through National Institutes of Health shared instrumentation Grant S10OD016374. The MoFlo XDP cell sorter was supported through National Institutes of Health Grants S10OD016315 and S10RR13777001.
Funding Information:
2 Recipient of National Nature Science Foundation of China Grant GP 81673492.
Funding Information:
This work was supported by National Institutes of Health Grant R01 GM065137. The authors declare that they have no conflicts of interest with the contents of this article. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
Publisher Copyright:
© 2018 by The American Society for Biochemistry and Molecular Biology, Inc.
PY - 2018/1/12
Y1 - 2018/1/12
N2 - The islet-specific zinc transporter ZnT8 is a major self-antigen found in insulin granules of pancreatic β-cells. Frequent insulin secretion exposes ZnT8 to the cell surface, but the humoral antigenicity of the surface-displayed ZnT8 remains unknown. Here we show that a membrane-embedded human ZnT8 antigen triggered a vigorous immune response in ZnT8 knock-out mice. Approximately 50% of serum immunoreactivities toward ZnT8 were mapped to its transmembrane domain that is accessible to extracellular ZnT8 antibody (ZnT8A). ZnT8A binding was detected on live rat insulinoma INS-1E cells, and the binding specificity was validated by a CRISPR/ Cas9 mediated ZnT8 knock-out. Applying established ZnT8A assays to purified serum antibodies from patients with type 1 diabetes, we detected human ZnT8A bound to live INS-1E cells, whereas a ZnT8 knock-out specifically reduced the surface binding. Our results demonstrate that ZnT8 is a cell surface self-antigen, raising the possibility of a direct involvement in antibody-mediated β-cell dysfunction and cytotoxicity.
AB - The islet-specific zinc transporter ZnT8 is a major self-antigen found in insulin granules of pancreatic β-cells. Frequent insulin secretion exposes ZnT8 to the cell surface, but the humoral antigenicity of the surface-displayed ZnT8 remains unknown. Here we show that a membrane-embedded human ZnT8 antigen triggered a vigorous immune response in ZnT8 knock-out mice. Approximately 50% of serum immunoreactivities toward ZnT8 were mapped to its transmembrane domain that is accessible to extracellular ZnT8 antibody (ZnT8A). ZnT8A binding was detected on live rat insulinoma INS-1E cells, and the binding specificity was validated by a CRISPR/ Cas9 mediated ZnT8 knock-out. Applying established ZnT8A assays to purified serum antibodies from patients with type 1 diabetes, we detected human ZnT8A bound to live INS-1E cells, whereas a ZnT8 knock-out specifically reduced the surface binding. Our results demonstrate that ZnT8 is a cell surface self-antigen, raising the possibility of a direct involvement in antibody-mediated β-cell dysfunction and cytotoxicity.
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U2 - 10.1074/jbc.RA117.000195
DO - 10.1074/jbc.RA117.000195
M3 - Article
C2 - 29184000
AN - SCOPUS:85041456734
SN - 0021-9258
VL - 293
SP - 579
EP - 587
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 2
ER -