Immunology Basics: Immunity Types

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Questions and Answers

What is the primary function of antibodies in the immune system?

To produce memory cells for future infections

To cause an immune response against harmless substances

To directly attack and destroy pathogenic cells

To identify and neutralize harmful antigens (correct)

Which immunoglobulin is specifically involved in allergic reactions?

IgE (correct)

IgA

IgM

IgG

What distinguishes active immunity from passive immunity?

Active immunity is temporary while passive immunity is long-lasting

Active immunity is acquired through medical procedures

Active immunity involves the production of antibodies while passive immunity does not (correct)

Active immunity results from a natural exposure to antigens

Which immunoglobulin is primarily found in blood and tissue fluids, protecting against viruses and bacteria?

IgG Signup and view all the answers

What is the key characteristic of natural immunity?

It is developed through normal biological experiences Signup and view all the answers

Which type of vaccine is created from a weakened live version of a pathogen?

Attenuated vaccine Signup and view all the answers

What type of immunity is derived from antibodies passed from mother to child through the placenta?

Natural passive immunity Signup and view all the answers

Which type of vaccine is made from killed versions of viruses and often requires booster shots?

Inactivated vaccine Signup and view all the answers

Which vaccine type resembles viruses but lacks viral genetic material?

Virus-like particle (VLP) vaccine Signup and view all the answers

What is the main purpose of administering DNA vaccines?

To stimulate a humoral and cellular immune response Signup and view all the answers

What is the role of mRNA in mRNA vaccines?

To deliver genetic instructions for making antigens. Signup and view all the answers

Why are booster shots necessary?

To enhance the body’s immune memory and response. Signup and view all the answers

What condition does congenital immunodeficiency specifically refer to?

Defects or missing genes present from birth. Signup and view all the answers

Which type of hypersensitivity reaction occurs within 30 minutes?

Anaphylactic Signup and view all the answers

What is a common misconception regarding vaccines and autism?

Vaccines directly cause autism in infants. Signup and view all the answers

What characterizes adaptive immunity compared to innate immunity?

It involves specific defenses that must be developed to recognize pathogens. Signup and view all the answers

Which process is primarily associated with B lymphocytes?

Secreting immunoglobulins to neutralize extracellular threats. Signup and view all the answers

What triggers an immunizing event?

The introduction of a vaccine into the bloodstream. Signup and view all the answers

What occurs during the primary immune response?

B and T lymphocytes are activated, proliferate, and differentiate upon encountering an antigen for the first time. Signup and view all the answers

How does the secondary immune response differ from the primary immune response?

It occurs when the immune system is exposed to the same antigen again, leading to a faster and stronger reaction. Signup and view all the answers

What is the primary role of histamine during anaphylactic shock?

Increases the permeability of blood capillaries Signup and view all the answers

Which treatment is used to address systemic anaphylaxis?

Epinephrine Signup and view all the answers

What defines a localized anaphylactic reaction?

Limited to specific body regions Signup and view all the answers

Which blood type can receive blood from any type without risk of reaction?

Type AB Signup and view all the answers

What is the primary cause of systemic anaphylaxis?

Ingested antigens or bee stings Signup and view all the answers

What is the main consequence of a Rh- mother having a Rh+ fetus during pregnancy?

The mother produces anti-Rh antibodies that can harm the fetus. Signup and view all the answers

Which of the following examples is associated with type 3 immune complex reactions?

Serum sickness from some vaccines Signup and view all the answers

What is the role of RhoGAM in the context of Rh factor incompatibility?

To prevent the production of anti-Rh antibodies in the mother. Signup and view all the answers

Which mechanism is involved in type 4 delayed cell-mediated reactions?

T cells activating memory cells after initial sensitization. Signup and view all the answers

Which factor contributes to the higher prevalence of autoimmune diseases in women?

Hormonal differences affecting immune tolerance. Signup and view all the answers

What is the main cause of intestinal damage in celiac disease?

Exposure to gluten in certain grains Signup and view all the answers

Which condition is characterized by T cells attacking insulin-secreting cells?

Diabetes type 1 Signup and view all the answers

What is the most significant consequence of systemic lupus erythematosus?

Damage to kidney glomeruli Signup and view all the answers

Which autoimmune condition is linked with symptoms like goiter and bulging eyes?

Graves' Disease Signup and view all the answers

Why are viruses classified as non-living entities?

They do not have a cellular structure. Signup and view all the answers

Study Notes

Adaptive Immunity vs. Innate Immunity

Adaptive immunity is specific and acquired, responding to threats through B and T cells.
Innate immunity is nonspecific and provides a general defense against pathogens.

Humoral vs. Cellular Immunity

Humoral Immunity: Focuses on extracellular threats, involving B cells that produce antibodies to neutralize pathogens.
Cellular Immunity: Targets intracellular threats, involving T cells that directly destroy infected cells.

Immunizing Event

An immunizing event triggers the immune system to develop defenses against a specific pathogen.
This results in B and T cell activation, replication, and differentiation into effector cells.
Memory cells are also produced, providing faster and stronger responses to future exposures.

Primary and Secondary Immune Responses

Primary Response: The initial encounter with an antigen, leading to activation and differentiation of B and T cells.
Secondary Response: A faster and more robust response due to the presence of memory cells from the primary response.

Antigens

Antigens are molecules on cell surfaces that identify cell type.
Antigens can trigger immune responses, and antibodies target specific antigens for destruction.

Immunoglobulins (Antibodies)

Immunoglobulins are soluble proteins produced by B cells or plasma cells.
Five major classes: IgM, IgG, IgA, IgE, IgD.
IgG: Predominant antibody in circulation, protects against bacteria, toxins, and viruses.
IgM: First antibody produced during an infection; important in ABO blood group reactions.
IgE: Involved in allergic reactions.

Natural vs. Artificial Immunity

Natural Immunity: Acquired through normal biological experiences.
Artificial Immunity: Acquired through medical procedures (e.g., vaccines).

Active vs. Passive Immunity

Active Immunity: Acquired when the body produces its own immune response to an antigen.
Passive Immunity: Acquired when antibodies are transferred from another source, providing temporary protection.

Vaccines

Vaccines provide artificial active immunity.
Types of Vaccines:
- Attenuated: Weakened live version of a pathogen.
- Inactivated: Killed version of a pathogen.
- Subunit: Contains pieces of a pathogen.
- Recombinant: Contains a modified version of a pathogen gene.
- Virus-like particle (VLP): Resembles a virus, but lacks genetic material.
- Polysaccharide: Made from molecules in pathogen capsules.
- DNA vaccines: Inject DNA coding for antigens.

mRNA Vaccines

Utilize mRNA enclosed in lipid nanoparticles to deliver genetic material for antigens.
Example: COVID-19 vaccines.

Reasons for Immunizing Infants

To protect infants from serious diseases and help their immune systems develop.

Boosters

Boosters are necessary to trigger a stronger secondary antibody response.

Vaccine Safety

Vaccines are safe and effective and do not cause autism.
Low vaccination rates contribute to outbreaks of preventable diseases.

Immunodeficiencies

Congenital Immunodeficiencies: Present at birth due to genetic defects.
Acquired Immunodeficiencies: Develop during a lifetime, like HIV/AIDS.

Hypersensitivity Reactions

Involve exaggerated immune responses to typically harmless antigens.
Types of Hypersensitivity Reactions:
- Type I (Anaphylactic): Immediate, IgE-mediated reactions (e.g., allergies).
- Type II (Cytotoxic): Antibody-mediated destruction of cells (e.g., transfusion reactions).
- Type III (Immune Complex): Antigen-antibody complexes activate complement (e.g., systemic lupus erythematosus).
- Type IV (Delayed Cell Mediated): T cell-mediated reactions (e.g., contact dermatitis).

Type I: Anaphylactic Shock

Localized Anaphylaxis: Restricted to a specific area, less severe.
Systemic Anaphylaxis: Affects cardiovascular and respiratory systems, potentially life-threatening.
Epinephrine is used to treat anaphylactic shock.

Type II: Cytotoxic Reactions

Antibody-mediated reactions that destroy cells via complement activation or macrophage action.
Blood type incompatibility is an example.

Rh Factor

Rh+ individuals have the Rh factor protein. Rh- individuals lack it.
Rh- mothers can develop anti-Rh antibodies during pregnancy with an Rh+ fetus, potentially harming the fetus (hemolytic disease of the newborn).

Type III: Immune Complex Reactions

Antibody-antigen complexes circulate in the blood.
Immune complexes activate complement and cause inflammation.
Examples: Serum sickness, systemic lupus erythematosus, rheumatoid arthritis.

Type IV: Delayed Cell-Mediated Reactions

T cell-mediated reaction, delayed response (24-48 hours).
Example: Contact dermatitis.

Autoimmune Diseases

Occurs when the immune system attacks self-antigens.
Causes: Loss of self-tolerance.
Examples: Lupus, diabetes, multiple sclerosis, celiac disease.

Multiple Sclerosis

Immune cells attack myelin sheath of nerves, leading to neurological damage.

Celiac Disease

Autoimmune reaction to gluten, damaging the small intestine.

Immune Complex Autoimmune Reactions

Systemic Lupus Erythematosus: Autoantibodies attack DNA, affecting kidney function.
Rheumatoid Arthritis: Autoantibodies target joints, damaging cartilage.
Graves' Disease: Autoantibodies mimicking TSH causing hyperthyroidism.

Cell-Mediated Autoimmune Reactions

Diabetes Type 1: T cells destroy insulin-producing cells in the pancreas.
Psoriasis and Psoriatic Arthritis: T cells attack skin and joints.

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Description

Explore the differences between adaptive and innate immunity, and understand the roles of humoral and cellular immunity. This quiz examines immunizing events, as well as primary and secondary immune responses to pathogens. Test your knowledge on how the immune system responds to threats.