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Questions and Answers
What is the primary reason why antibodies do not recognize structures on our own cells?
What is the primary reason why antibodies do not recognize structures on our own cells?
What are the four blood types determined by the presence of A and B antigens on red blood cells?
What are the four blood types determined by the presence of A and B antigens on red blood cells?
What can happen during a mismatched blood transfusion?
What can happen during a mismatched blood transfusion?
How are anti-Rh antibodies induced in an Rh- mother?
How are anti-Rh antibodies induced in an Rh- mother?
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What is the consequence of sepsis in the context of an infection?
What is the consequence of sepsis in the context of an infection?
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Which process is primarily responsible for generating a diverse pool of lymphocytes?
Which process is primarily responsible for generating a diverse pool of lymphocytes?
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What leads to the deletion or inactivation of self-reactive B cells during development?
What leads to the deletion or inactivation of self-reactive B cells during development?
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What triggers the production of antibodies that bind A or B antigens in individuals?
What triggers the production of antibodies that bind A or B antigens in individuals?
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What is the primary function of inflammatory cytokines in the body?
What is the primary function of inflammatory cytokines in the body?
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Which cells release allergic mediators in response to allergen exposure?
Which cells release allergic mediators in response to allergen exposure?
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What condition can result from systemic allergen exposure?
What condition can result from systemic allergen exposure?
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What role do IgE antibodies play in allergic responses?
What role do IgE antibodies play in allergic responses?
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Which of the following is NOT a symptom of an acute allergic response?
Which of the following is NOT a symptom of an acute allergic response?
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In allergic responses, what is the first step during initial allergen exposure?
In allergic responses, what is the first step during initial allergen exposure?
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How can drugs become antigenic?
How can drugs become antigenic?
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What can be a consequence of allergic mediators released during mast cell degranulation?
What can be a consequence of allergic mediators released during mast cell degranulation?
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Study Notes
Can the Immune System Be a Source of Disease?
- The immune system can be a source of disease.
- This occurs when the immune system mistakenly attacks the body's own tissues or is overly reactive to harmless substances.
What Kind of Structures do Antibodies Recognize?
- Antibodies recognize specific structures on pathogens, called antigens.
- Lymphocyte development creates a wide range of lymphocytes, each with unique specificity for different antigens.
- This variety of lymphocytes protects the body from a diverse range of pathogens.
Immune Tolerance
- Self-reactive lymphocytes, which target the body's own cells, are normally eliminated or suppressed during development.
- This process is called "negative selection".
- As B cells develop in the bone marrow, they rearrange immunoglobulin gene segments to create diverse specificities.
- If a B cell's immunoglobulin binds to self-antigens, it undergoes programmed cell death (apoptosis) or is rendered inactive.
Human ABO Antigens and Blood Types
- Individuals express glycolipids on red blood cells with terminal carbohydrate structures (A, B, or O).
- There are four blood types: A, B, AB, and O.
- Blood type is determined by the combination of alleles.
- Individuals produce antibodies against antigens not present on their own blood cells.
- Exposure to microbial pathogens with similar structures can induce antibody production.
Mismatched Blood Transfusions
- Mismatched blood transfusions can lead to serious complications.
- Antibodies from the recipient can bind to the donor's red blood cells (RBCs), initiating a complement-mediated response.
- This can cause hemolysis (destruction of RBCs) leading to severe consequences.
- Blood typing is essential to prevent these issues, ensuring compatibility between donor and recipient blood.
Rhesus (Rh) Factor
- Rh is another red blood cell antigen whose expression varies between individuals.
- Anti-Rh antibodies are not naturally present but are formed following exposure to Rh+ blood.
- This typically happens during pregnancy when an Rh- mother carries an Rh+ fetus.
- Anti-Rh antibodies produced during the first pregnancy may damage red blood cells of subsequent Rh+ fetuses.
- Anti-Rh antibodies can be administered directly following the initial pregnancy to prevent sensitization.
Immunopathology Associated With Pathogen Infection
- Inflammatory mediators, like cytokines, help bring immune cells to the site of infection.
- The inflammatory response usually locates the infection site.
- Excessive or systemic inflammation can be harmful.
Sepsis
- Sepsis is a life-threatening condition caused by a body-wide inflammatory response to an infection (typically a bacterial infection).
- Inflammation throughout the body leads to blood vessel damage. This results in loss of blood volume and can cause circulatory shock and death.
Allergy
- Allergies are a strong immune response directed to harmless substances.
- Allergens bind to IgE antibodies on mast cells, triggering the release of inflammatory mediators (e.g., histamine).
- These mediators cause allergic symptoms like itching, swelling, and difficulty breathing in affected tissues.
- Mast cells primarily reside within tissues in response to pathogens.
Allergic Responses Require Sensitization
- Allergen exposure first results in the immune system's training to recognize the allergen.
- Subsequent exposures trigger the release of inflammatory mediators causing allergic symptoms.
Allergic Mediators
- Allergic mediators released by degranulating mast cells trigger inflammatory responses which promote clearance of allergens from mucosal surfaces.
- Symptoms depend upon the site of exposure. For example, respiratory tract exposure would present differently than gatrointestinal tract exposure.
- Systemic allergy may be life-threatening.
Allergic Responses
- Systemic reactions are potentially deadly and are called anaphylaxis.
- Anaphylaxis is characterized by increased blood vessel permeability, decreased blood volume, and airway constriction leading to potentially life-threatening symptoms and requiring immediate medical treatment.
Immune Response to Drugs
- Drugs, like penicillin, are not normally antigenic. But if they attach to host proteins, they become antigenic.
- This results in the immune system creating antibodies against these modified proteins.
- Repeated exposure to these drugs can worsen the response, as the immune system is further activated and creates more antibodies.
T Cells and Hypersensitivity
- T cells can mediate hypersensitivity reactions (e.g., contact dermatitis, some autoimmune disorders).
- In contact dermatitis, substances change host proteins, becoming antigens that T cells recognize.
- Subsequent exposure elicits a delayed-type hypersensitivity reaction at the site of exposure. This inflammatory reaction occurs over several days.
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Description
This quiz explores key concepts of the immune system, including how it can inadvertently be a source of disease. Questions cover antibody recognition of pathogens, the process of immune tolerance, and the development of lymphocytes. Test your knowledge on these fundamental immunological processes!
