Viewing Autoimmune Pathogenesis from the Perspective of Antigen Processing and Determinant Hierarchy

Area of Science:

• Immunology
• Autoimmunity Research
• T Cell Biology

Background:

• Autoimmunity stems from a loss of immune tolerance to self antigens.
• Antigen-presenting cells (APCs) process self antigens, presenting dominant epitopes that are usually ignored by T cells due to thymic deletion.
• T cells recognizing cryptic epitopes, which are poorly processed, escape tolerance and can be activated under inflammatory conditions.

Purpose of the Study:

• To explain the immunological mechanisms underlying autoimmunity.
• To elucidate the role of cryptic epitopes and epitope spreading in autoimmune disease initiation and progression.
• To present a conceptual framework integrating T cell selection and autoimmunity.

Main Methods:

• Conceptual analysis of immune tolerance and self-antigen processing.
• Review of T cell selection processes in the thymus and periphery.
• Integration of findings on epitope hierarchy and immune activation in autoimmunity.

Main Results:

• Normally ignored cryptic self epitopes can be presented during inflammation, activating self-reactive T cells.
• Epitope spreading, the response to newly revealed epitopes, can propagate autoimmunity.
• The framework links T cell selection, determinant hierarchy, and autoimmune disease dynamics.

Conclusions:

• Breakdown of immune tolerance initiates autoimmunity, often involving cryptic epitopes.
• Epitope spreading can either drive disease progression or contribute to its natural regression.
• The conceptual model provides a unified understanding of autoimmunity induction and propagation.