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Questions and Answers
What do hypersensitivity reactions primarily involve?
Which of the following best describes autoimmunity?
In individuals abnormally responsive to environmental substances, what type of antibody is primarily produced?
What is unique to allergic diseases regarding hypersensitivity reactions?
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What is a key characteristic of hypersensitivity diseases regarding immune responses?
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What predominantly causes disease in hypersensitivity reactions?
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Which type of autoantibody acts as a receptor agonist?
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In Graves' disease, which receptor do autoantibodies primarily target?
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What type of antigens may be targeted in hypersensitivity reactions?
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What is the main effect of autoantibodies that act as receptor antagonists?
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Which population segment is likely to be abnormally responsive to environmental allergens?
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How do the failure mechanisms of self-tolerance lead to autoimmunity?
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Which of the following diseases is associated with autoantibodies against the TSH receptor?
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What occurs when antibodies against streptococcal cell-wall antigens cross-react with heart tissue?
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Which hypersensitivity reactions correspond to allergic diseases, transplantation, and autoimmune diseases?
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What is a consequence of thyroid epithelial cells making thyroglobulin in presence of iodide?
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What is the primary mechanism causing many organ-specific autoimmune diseases?
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Which of the following conditions is primarily characterized by the destruction of insulin-producing cells?
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What characterizes the histological examination of a pancreas in a patient with acute onset type 1 diabetes?
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Which cytokines are primarily involved in granuloma formation during prolonged immune reactions?
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What characterizes the thyroid hormone production in patients with Graves’ disease?
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What is the purpose of sensitization in the delayed-type hypersensitivity reaction?
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What role do autoantibodies play in myasthenia gravis?
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Which type of immune cells primarily infiltrate the granulomas found in tuberculosis?
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How do antibodies function as agonists and antagonists?
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What primarily mediates the mechanism of autoimmunity in diseases caused by antibodies?
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What is a significant feature of delayed-type hypersensitivity (DTH) reactions?
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In the context of immune response against intracellular microbes, what role do T lymphocytes play?
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What is one mechanism by which red blood cells are destroyed in autoimmune hemolytic anemia?
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Which of the following describes the endocytosis effect caused by autoantibodies in myasthenia gravis?
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What happens to the neuromuscular junction in patients with myasthenia gravis?
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What is one consequence of complement fixation on the surface of red blood cells in autoimmune hemolytic anemia?
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What is the process called when subsequent exposure to the same antigen elicits a reaction?
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Which protein antigen is used in the tuberculin skin test (TST)?
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What type of hypersensitivity reaction is the tuberculin reaction classified as?
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Which autoantibodies are commonly produced by patients with rheumatoid arthritis?
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What is the primary goal of current treatments for autoimmune diseases?
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What is the significance of a positive tuberculin skin test response?
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Which cytokine antagonist is commonly used in the treatment of rheumatoid arthritis?
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What is the primary mechanism by which exposure to microbial infections can sensitize humans for delayed-type hypersensitivity reactions?
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Study Notes
Hypersensitivity Reactions
- Harmful immune responses against foreign antigens
- Can occur against environmental antigens, drugs, and microbes
Types of Hypersensitivity Reactions
- Type I: IgE-mediated reactions, responsible for allergic diseases
- Type II: Antibody-mediated cytotoxicity, involves antibodies against cell surface antigens
- Type III: Immune complex-mediated reactions, caused by antibody-antigen complexes
- Type IV: T cell-mediated reactions, involves delayed hypersensitivity
Autoimmunity
- Immune responses against self-antigens
- Failure of self-tolerance leads to reactions against body's own cells and tissues
Allergy
- Individuals respond abnormally to common environmental substances
- Produces IgE antibodies, causing various allergic diseases
Transplantation
- Reactions against non-microbial antigens
- Immune responses may cause disease if reactions are excessive
Autoimmunity and Microbes
- Most individuals don't react to common, harmless environmental substances
- Autoimmunity may cause disease if reactions against microbial antigens are excessive
- Microbes that are unusually resistant to eradication may result in persistent infections
IgE Antibodies
- Play a critical role in type I hypersensitivity reactions
- Bind to mast cells, releasing histamine and other inflammatory mediators
Cell-Mediated Immune Responses
- Major mechanism underlying rheumatoid arthritis, multiple sclerosis (MS), type 1 diabetes, psoriasis, and other autoimmune diseases
- T cells recognize self-antigens and activate immune responses, leading to inflammation and tissue damage
Type 1 Diabetes
- Caused by autoreactive T cells that destroy insulin-producing pancreatic cells
- Immune responses against islet cells disrupt insulin production
Granulomatous Inflammation
- A type of chronic inflammation characterized by the formation of granulomas, aggregates of immune cells
- Triggered by persistent antigens, such as bacteria or fungi
- Macrophages, lymphocytes, and giant cells contribute to granuloma formation
Delayed-Type Hypersensitivity (DTH) Reaction
- Delayed hypersensitivity reaction mediated by T cells
- Requires previous sensitization to a specific antigen
- Manifested as inflammation and tissue damage after re-exposure to the antigen
- Examples include tuberculin reaction
Rheumatoid Arthritis (RA)
- Chronic autoimmune disorder
- Characterized by inflammation of joints
- Caused by autoreactive T cells and antibodies targeting joint tissues
Systemic Lupus Erythematosus (SLE)
- Chronic autoimmune disease
- Characterized by autoantibodies against nuclear antigens
- Affects multiple organs and tissues
Treatment of Autoimmune Diseases
- Goal is to reduce immune activation and inflammation
- Therapeutic approaches include immunosuppressive drugs, biological therapies, and lifestyle modifications
- Anti-TNF-α therapies target tumor necrosis factor-alpha, a key inflammatory cytokine
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Description
This quiz explores the various types of hypersensitivity reactions and their mechanisms, including type I through type IV classifications. It also covers autoimmune responses and how they can result in harmful reactions against the body's own tissues. Test your knowledge on allergies, transplantation, and the interactions between autoimmunity and microbes.
