ImmunologyLesson 2 of 5 in the course Diseases of the Immune System

Autoimmune Tolerance, Mechanisms, and Major Disorders

5 flashcards · 5 quiz questions · 5 match pairs · 5 fill-in sentences · English

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Summary

This lesson explains how the immune system can mistakenly attack the body and why autoimmune disorders develop. Understanding immune tolerance and the possible contributors to its failure provides a foundation for studying specific diseases.

The adaptive immune system normally distinguishes foreign targets, such as pathogens, from the body's own cells. Immune tolerance is the absence of an immune response against self-antigens. When tolerance is lost, self-reactive immune cells or antibodies can attack the body's own tissues. This condition is called autoimmunity, and diseases caused by such attacks are autoimmune diseases.

All flashcards

What is an autoimmune disease?
A disease caused by an inappropriate adaptive immune response directed against the body's own cells or tissues.
What is immune tolerance?
The absence of an immune response against self-antigens.
How can regulatory T cells help maintain self-tolerance?
They inhibit self-reactive T cells, including some that escaped elimination during thymic selection.
How can antigen mimicry contribute to autoimmunity?
A pathogen antigen resembling a self-antigen can cause an immune response to cross-react with the body's tissues.
Which hypersensitivity types can cause tissue injury in autoimmune disease?
Type II, type III, and type IV hypersensitivity reactions.

Quiz questions

  1. In type 1 diabetes, which cells are destroyed by the autoimmune response, reducing insulin production?Answer: Insulin-producing β cells in the pancreatic islets.
  2. Which structure is damaged by inflammatory lesions in multiple sclerosis?Answer: The myelin sheath around nerve fibers in the central nervous system.
  3. In myasthenia gravis, what do the characteristic autoantibodies target?Answer: Acetylcholine receptors at neuromuscular junctions.
  4. How does thyroid-stimulating immunoglobulin contribute to Graves disease?Answer: It binds and stimulates the TSH receptor, increasing thyroid activity.
  5. Which statement about antinuclear antibodies (ANAs) in systemic lupus erythematosus is accurate?Answer: They are common in SLE, but a positive ANA result alone is not diagnostic.

Based on Microbiology by Nina Parker, Mark Schneegurt, Anh-Hue Thi Tu, Philip Lister, Brian M. Forster (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.

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