Human clonal CD8 autoreactivity to an IGRP islet epitope shared between mice and men

Area of Science:

• Immunology
• Endocrinology
• Molecular Biology

Background:

• Type 1 diabetes (T1D) involves autoimmune destruction of pancreatic beta cells by T cells.
• CD8(+) T cells are critical mediators of beta cell destruction in T1D.
• Identifying specific T cell targets is crucial for understanding T1D pathogenesis.

Purpose of the Study:

• To investigate if the islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP) (265-273) epitope is a target of human diabetogenic CD8(+) T cells.
• To determine if this IGRP epitope, identified in non-obese diabetic mice, is relevant in human T1D.
• To confirm cross-species antigen sharing in T1D autoimmunity.

Main Methods:

• Isolation of a human CD8 T cell clone.
• Epitope mapping using the IGRP (265-273) sequence.
• Cross-species homology analysis of the IGRP epitope.

Main Results:

• A human CD8 T cell clone specifically recognizing the IGRP (265-273) epitope was successfully isolated.
• This confirms that the IGRP (265-273) epitope is recognized by human CD8(+) T cells in the context of T1D.
• The identified epitope is homologous between mouse models and humans, suggesting conserved autoimmune targets.

Conclusions:

• The islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP) (265-273) epitope is a target of human diabetogenic CD8(+) T cells.
• This finding highlights the potential role of IGRP in human T1D pathogenesis.
• The shared nature of this epitope across species provides a valuable insight for developing T1D immunotherapies.