Epitope spreading refers to which of the following?

Epitope spreading refers to which of the following?

• A. Post-translational modifications to self-antigens.
• B. Modifications in gene expression that are not caused by changes in DNA sequence.
• C. Expansion of the immune response to unrelated antigens
• D. Cross-reaction of the immune response to a pathogen with a similar self-antigen.

Answer: (C)

Epitope spreading describes the immune system broadening its targets from the initial epitope to additional epitopes over time. As the response evolves, tissue damage and the release of new antigens expose more epitopes to antigen-presenting cells. Those epitopes are then presented to T cells and recognized by B cells, leading to the generation of new adaptive responses against these newly encountered epitopes. This can happen within the same antigen (intramolecular spreading) or to different antigens (intermolecular spreading), and it can contribute to worsening autoimmune diseases by expanding the pool of targets the immune system attacks. That makes expanding to additional, sometimes unrelated, epitopes the best match for epitope spreading. By contrast, post-translational modifications to self-antigens are changes to antigen structure, not an expansion of epitopes targeted by the immune system. Epigenetic changes involve gene expression without altering DNA sequence, not antigen-specific diversification. Cross-reaction with a pathogen due to similar self-antigens describes molecular mimicry, a related but distinct mechanism from epitope spreading.

Epitope spreading describes the immune system broadening its targets from the initial epitope to additional epitopes over time. As the response evolves, tissue damage and the release of new antigens expose more epitopes to antigen-presenting cells. Those epitopes are then presented to T cells and recognized by B cells, leading to the generation of new adaptive responses against these newly encountered epitopes. This can happen within the same antigen (intramolecular spreading) or to different antigens (intermolecular spreading), and it can contribute to worsening autoimmune diseases by expanding the pool of targets the immune system attacks. That makes expanding to additional, sometimes unrelated, epitopes the best match for epitope spreading.

By contrast, post-translational modifications to self-antigens are changes to antigen structure, not an expansion of epitopes targeted by the immune system. Epigenetic changes involve gene expression without altering DNA sequence, not antigen-specific diversification. Cross-reaction with a pathogen due to similar self-antigens describes molecular mimicry, a related but distinct mechanism from epitope spreading.