Types of Immune Response: Hypersensitivity
24 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What defines a hypersensitivity reaction and how does it differ from a normal immune response?

A hypersensitivity reaction is an exaggerated immune response to harmless antigens, unlike a normal immune response that is proportionate and protective.

Describe the role of immunoglobulin E (IgE) in Type I hypersensitivity reactions.

IgE binds to mast cells, triggering immediate allergic reactions upon re-exposure to the sensitizing antigen.

Explain the significance of atopy in Type I hypersensitivity reactions.

Atopy refers to a genetically determined predisposition to allergic reactions, often leading to conditions like asthma and allergic rhinitis.

Compare Type I and Type II hypersensitivity reactions in terms of their pathogenesis.

<p>Type I hypersensitivity is mediated by IgE and involves immediate reactions, while Type II hypersensitivity is mediated by IgG/IgM and involves antibody-mediated damage to cells.</p> Signup and view all the answers

What types of antigens can trigger hypersensitivity reactions, and how are they categorized?

<p>Hypersensitivity reactions can be triggered by exogenous (environmental) or endogenous (self) antigens, categorized into four types based on their mechanism.</p> Signup and view all the answers

Outline the role of TH2 lymphocytes in allergic responses associated with Type I hypersensitivity.

<p>TH2 lymphocytes secrete IL-4, promoting IgE production and enhancing the allergic response in sensitized individuals.</p> Signup and view all the answers

What is the clinical relevance of distinguishing between different types of hypersensitivity reactions?

<p>Differentiating hypersensitivity types aids in diagnosing and treating specific allergic conditions effectively.</p> Signup and view all the answers

How does family history influence the likelihood of developing atopy and associated allergic diseases?

<p>Familial associations indicate that genetic factors can predispose individuals to atopy, increasing their risk for allergic diseases.</p> Signup and view all the answers

What are the clinical manifestations of localized hypersensitivity reactions like hay fever?

<p>The clinical manifestations include redness, sneezing, and a runny nose.</p> Signup and view all the answers

What role do IgG and IgM antibodies play in Type II hypersensitivity reactions?

<p>IgG and IgM antibodies bind to antigens on cell surfaces, leading to cell destruction or altered function.</p> Signup and view all the answers

Describe the process of opsonization in Type II hypersensitivity reactions.

<p>Opsonization involves antibodies coating antigens on cells, which enhances phagocytosis by immune cells.</p> Signup and view all the answers

How does the complement system contribute to the effects of Type II hypersensitivity?

<p>The complement system is activated by antibody-antigen binding, leading to inflammation and cell lysis.</p> Signup and view all the answers

What are some clinical examples of complement-mediated inflammation in Type II hypersensitivity?

<p>Examples include transplant organ rejection and skin rashes due to drug reactions.</p> Signup and view all the answers

What is erythroblastosis fetalis and its mechanism related to Type II hypersensitivity?

<p>Erythroblastosis fetalis occurs when maternal IgG antibodies cross the placenta, attacking fetal red blood cells.</p> Signup and view all the answers

Explain how drug reactions can trigger Type II hypersensitivity.

<p>Drug reactions occur when antibodies form against drug-modified cell surfaces, resulting in cell damage.</p> Signup and view all the answers

Identify the role of macrophages and neutrophils in Type II hypersensitivity reactions.

<p>Macrophages and neutrophils are recruited to sites of antigen-antibody binding, mediating inflammation.</p> Signup and view all the answers

What role does Immunoglobulin E (IgE) play in the mechanism of Type I hypersensitivity reactions?

<p>IgE is produced in response to allergen exposure and binds to mast cells, leading to their activation upon subsequent allergen exposure.</p> Signup and view all the answers

How does the early phase of a Type I hypersensitivity reaction differ from the late phase?

<p>The early phase occurs 5–30 minutes after allergen exposure with immediate symptoms, while the late phase occurs 4–12 hours later, causing tissue damage and inflammation.</p> Signup and view all the answers

What are the primary effector cells involved in Type I hypersensitivity reactions and their roles?

<p>Mast cells in tissues and basophils in blood are the primary effector cells, releasing mediators that cause allergic symptoms.</p> Signup and view all the answers

What clinical manifestations are associated with systemic anaphylactic reactions?

<p>Clinical manifestations include itching, hives, respiratory distress, and laryngeal edema.</p> Signup and view all the answers

Which cytokine is most potent in activating eosinophils during the late phase of hypersensitivity reactions?

<p>Interleukin-5 (IL-5) is the most potent eosinophil-activating cytokine.</p> Signup and view all the answers

List some exogenous environmental antigens that can trigger Type I hypersensitivity reactions.

<p>Examples include pollen grains, dust, food components, and animal dander.</p> Signup and view all the answers

What happens to mast cells upon re-exposure to the same allergen in sensitized individuals?

<p>Mast cells degranulate and release mediators upon re-exposure to the allergen.</p> Signup and view all the answers

How do leukotrienes and prostaglandins contribute to Type I hypersensitivity reactions?

<p>Leukotrienes and prostaglandins are mediators released from mast cells that enhance inflammation and smooth muscle contraction.</p> Signup and view all the answers

Flashcards

Hypersensitivity Reactions

A heightened immune response to typically harmless antigens, leading to an exaggerated reaction.

Type I Hypersensitivity

An abnormal immune response involving the production of IgE antibodies, which bind to mast cells and release histamine upon contact with the allergen.

Atopy

A term for individuals who have a genetic predisposition to developing allergies, often showing elevated IgE levels in their blood.

Anaphylactic Reaction

The release of histamine and other inflammatory mediators from mast cells, causing rapid symptoms like hives, swelling, and difficulty breathing.

Signup and view all the flashcards

Type II Hypersensitivity

A type of hypersensitivity reaction that involves the destruction of cells by antibodies directed against specific antigens on the cell surface.

Signup and view all the flashcards

Blood Group Incompatibility

A condition that occurs when an individual receives blood from a donor with incompatible blood antigens, triggering a destructive immune response.

Signup and view all the flashcards

Autoimmune Reactions

A group of immune disorders characterized by a failure of the immune system to recognize and eliminate self-antigens, leading to the destruction of body tissues.

Signup and view all the flashcards

Immunodeficiency

Conditions caused by an impaired immune system, making individuals more susceptible to infections.

Signup and view all the flashcards

Allergen

Antigen that triggers an allergic reaction, often found in the environment.

Signup and view all the flashcards

Immunoglobulin E (IgE)

An antibody that plays a key role in allergic reactions, binding to mast cells.

Signup and view all the flashcards

Mast cells

Cells that release histamine and other chemicals during an allergic reaction.

Signup and view all the flashcards

Anaphylaxis

A severe allergic reaction that can be life-threatening. Symptoms include widespread swelling, difficulty breathing, and low blood pressure.

Signup and view all the flashcards

Early phase reaction

The release of histamine and other chemicals from mast cells within minutes of exposure to an allergen.

Signup and view all the flashcards

Late phase reaction

Inflammatory response that occurs hours after the initial allergic reaction, involving cells like eosinophils and neutrophils.

Signup and view all the flashcards

Histamine

Chemical released by mast cells during allergic reaction, causing symptoms like itching, swelling, and redness.

Signup and view all the flashcards

Hemolytic Transfusion Reaction

A reaction that happens when mismatched blood is transfused, leading to destruction of red blood cells.

Signup and view all the flashcards

Hemolytic Disease of the Newborn

When a mother with Rh-negative blood carries an Rh-positive baby, antibodies can cross the placenta and destroy fetal red blood cells.

Signup and view all the flashcards

Autoimmune Anemia

Antibodies against red blood cells, which are part of the immune system, leading to anemia.

Signup and view all the flashcards

Autoimmune Disease

A reaction where the body mistakenly attacks its own cells and tissues.

Signup and view all the flashcards

Complement- and Fc Receptor-mediated Inflammation

Antigen-antibody binding triggers the complement system, leading to an inflammatory response. Neutrophils and macrophages contribute by releasing chemicals.

Signup and view all the flashcards

Complement-mediated Lysis

Antigen-antibody reaction on cell surfaces activates the complement cascade, leading to the destruction of cells.

Signup and view all the flashcards

Opsonization and Phagocytosis

Antibodies bind to antigens on cell surfaces, making them more appealing to phagocytes. These phagocytes then engulf and destroy the cells.

Signup and view all the flashcards

Study Notes

Types of Immune Response: Type I & II Hypersensitivity Reactions

  • Hypersensitivity reactions are exaggerated responses to harmless antigens, resulting from an imbalance between effector and regulatory mechanisms.
  • Individuals are considered sensitized if they have been previously exposed to the antigen.
  • Types I, II, and III hypersensitivity reactions are immediate, occurring within 24 hours. Type IV is a cellular reaction, developing over several days.
  • Type I Hypersensitivity (Atopy/Allergy):
    • A rapid response triggered by an antigen binding to IgE antibodies on mast cells in sensitized individuals.
    • Also known as anaphylactic reaction.
    • Involves an abnormal adaptive immune response that may or may not involve antigen-specific IgE.
  • Type II Hypersensitivity (Cytotoxic Hypersensitivity):
    • Antibodies target antigens on cell surfaces or in the extracellular matrix, leading to cell destruction, inflammation, or impaired function.
    • Can be caused by exogenous antigens (e.g., microbes, parasites, drugs) or endogenous antigens (e.g., in autoimmune diseases).
    • Antibodies like IgG and sometimes IgM are involved.
    • Effector cells include macrophages, neutrophils, eosinophils, and NK cells.
    • Three mechanisms are: opsonization and phagocytosis, complement and Fc receptor-mediated inflammation, and antibody-mediated cellular dysfunction.

Clinical Examples of Type I Hypersensitivity

  • Systemic anaphylactic reaction (anaphylactic shock): A potentially fatal reaction to allergens.
  • Localized hypersensitivity: Reactions localized to the site of allergen entry, such as hay fever (allergic rhinitis), bronchial asthma, food allergies, atopic dermatitis, and allergic conjunctivitis.

Clinical Examples of Type II Hypersensitivity

  • Hemolytic transfusion reaction: Mismatched blood transfusions triggering the destruction of blood cells.
  • Hemolytic disease of the newborn (erythroblastosis fetalis): Maternal antibodies attacking fetal red blood cells due to Rh incompatibility.
  • Autoimmune anemia: Antibodies attacking the body's own red blood cells.
  • Drug reactions: Immunological reactions to drugs.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Related Documents

Tissue Block 16 Lecture Notes PDF

Description

This quiz delves into the intricacies of Type I and II hypersensitivity reactions, highlighting their mechanisms and significance in the immune response. Understand the differences between anaphylactic reactions and cytotoxic hypersensitivity, as well as the role of antibodies and antigens. Perfect for students studying immunology and related fields.

More Like This

Hypersensitivity Reactions in Immunology
24 questions

Hypersensitivity Reactions in Immunology

StraightforwardStrait7672 avatar
StraightforwardStrait7672
Immunology Hypersensitivity Reactions Quiz
44 questions

Immunology Hypersensitivity Reactions Quiz

FoolproofBaritoneSaxophone1086 avatar
FoolproofBaritoneSaxophone1086
Types of Immune Response
20 questions

Types of Immune Response

SpiritualHonor avatar
SpiritualHonor
Types of Immune Response: Hypersensitivity
22 questions

Types of Immune Response: Hypersensitivity

SpiritualHonor avatar
SpiritualHonor
Use Quizgecko on...
Browser
Open
Browser
Browser