Immunology Overview Quiz

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Questions and Answers

What specific glycoprotein do NK cells recognize in virus-infected cells?

Surface Antigen

Glycoprotein on the cell surface (correct)

Major Basic Protein

Toll-like Receptor

Which immune cells are primarily responsible for secreting toxic enzymes to destroy large parasites like worms?

Eosinophils (correct)

Dendritic Cells

Macrophages

Neutrophils

What is a primary function of the complement system?

Produce antibodies

Enhance phagocytosis (correct)

Regulate blood pressure

Form tumors

How do macrophages contribute to the destruction of parasites after eosinophils have acted?

Engulf the parasites' elements (D) Signup and view all the answers

What role do the proteins in the complement system play in immune defense?

Directly lysing pathogens (A) Signup and view all the answers

What is the primary function of the thymus gland in the immune system?

To support the development of lymphocytes (A) Signup and view all the answers

Which type of immunity is acquired through exposure to a disease?

Naturally acquired adaptive immunity (A) Signup and view all the answers

Which of the following is an example of artificially acquired adaptive immunity?

Vaccination against influenza (C) Signup and view all the answers

How does innate immunity differ from adaptive immunity?

Innate immunity is present at birth, while adaptive immunity develops over time (B) Signup and view all the answers

Which cells are primarily responsible for the adaptive immune response?

Lymphocytes (C) Signup and view all the answers

What is the role of C3b in the immune response?

It induces the formation of the membrane attack complex. (B) Signup and view all the answers

Which complement fragments are primarily involved in enhancing inflammatory reactions?

C3a, C4a, and C5a. (A) Signup and view all the answers

What is the function of the membrane attack complex (MAC)?

To create lesions in the cell membranes of microorganisms. (C) Signup and view all the answers

Which of the following correctly describes opsonization?

The binding of complement proteins to enhance phagocytosis. (C) Signup and view all the answers

What triggers immune cytolysis?

The binding of C5 to C8 and C9. (D) Signup and view all the answers

What occurs as a result of C3b binding to microbial cell membranes?

Initiation of phagocytosis by immune cells. (B) Signup and view all the answers

Which complements undergo splitting to initiate the formation of the C5bC6C7 complex?

C5 and C3. (C) Signup and view all the answers

How do C3a, C4a, and C5a contribute to the inflammatory response?

By attracting additional phagocytes to the infection site. (C) Signup and view all the answers

What is the result of the leakage of fluid from blood vessels during inflammation?

Migration of leukocytes and phagocytes (A) Signup and view all the answers

Which mediator is primarily responsible for stimulating pain during inflammation?

Bradykinin (B) Signup and view all the answers

How does interferon help during viral infections?

By hindering viral replication in neighboring cells (D) Signup and view all the answers

What process describes the migration of phagocytes from blood vessels to tissue?

Diapedesis (C) Signup and view all the answers

What is one effect of increased blood vessel diameter during inflammation?

Increased blood flow (A) Signup and view all the answers

Which type of interferon is NOT found in humans?

Delta (δ) (C) Signup and view all the answers

How do Natural Killer (NK) Cells increase their activity?

Through cytokines and interferon (A) Signup and view all the answers

What role do pro-inflammatory mediators play during the inflammatory process?

They increase the diameter of blood vessels (D) Signup and view all the answers

What initiates the classical complement pathway during opsonization?

C1 binding to the opsonin (C) Signup and view all the answers

Which component of the complement system is directly activated by the contact with polysaccharides at the pathogen surface?

Complement proteins (D) Signup and view all the answers

What is the primary role of antibodies in the complement system?

To bind and coat pathogens (D) Signup and view all the answers

What occurs after C1 binds to the opsonin in the classical complement pathway?

C4 is activated into C4a and C4b (A), C2 is cleaved into C2a and C2b (C) Signup and view all the answers

Which best describes the overall function of the complement system?

Enhances the immune response through a cascade (B) Signup and view all the answers

How do bacteria avoid phagocytosis, and how does the complement system counteract this?

By having capsules or surface proteins, countered by opsonization (C) Signup and view all the answers

Which component directly initiates the cascade in the classical complement pathway?

C1 (D) Signup and view all the answers

In the complement system, what is the most likely consequence of the cleavage of C4?

Formation of C4a and C4b (B) Signup and view all the answers

What are the primary components of innate immunity?

Physical barriers, chemical barriers, cellular defenses (C) Signup and view all the answers

How do physical barriers like skin and mucous membranes protect the body?

By inhibiting pathogen entry through structural means (A) Signup and view all the answers

Which of the following is NOT a characteristic of adaptive immunity?

It is effective against new pathogens only (B) Signup and view all the answers

What is one function of lysozyme in the immune system?

To cleave bacterial cell walls (C) Signup and view all the answers

Which type of immune response is characterized by the production of antibodies?

Adaptive immunity (A) Signup and view all the answers

Which of the following processes is part of the body's innate defense mechanisms?

Inflammation and fever response (A) Signup and view all the answers

What type of cells are leukocytes and what is their primary function?

Defensive cells important to immunity (C) Signup and view all the answers

What role does the acidic pH of the stomach play in immunity?

It acts as a barrier against intestinal pathogens (B) Signup and view all the answers

Which of the following is an example of a chemical barrier in innate immunity?

Antimicrobial substances in body fluids (B) Signup and view all the answers

Study Notes

Learning Objectives

Students should be able to explain or identify terms in immunology.
Students should be able to explain innate immunity, components, and reactions.
Students should be able to explain adaptive immunity, components, and reactions.
Students should be able to explain phagocytosis.
Students should be able to explain molecular defenses.
Students should be able to explain the characteristics of inflammation.
Students should be able to explain the interferon and complement system.

Terminologies

Immunity: The ability of an organism to recognize and defend against infectious agents.
Susceptibility: The vulnerability of a host to harm by infectious agents, the opposite of immunity.
Antigen: A toxin or substance that triggers an immune response, specifically the production of antibodies.
Immune System: A network of cells and organs (e.g., thymus) that provide specific immunity against infectious agents.

Differences Between Antigen and Antibody

Antigen: A substance, often a part of a foreign body like a bacterial cell, that elicits an immune response.
Antibody: Molecules produced by the immune system to target and counteract antigens.

Types of Immunity

Innate (genetic) immunity: Immunity determined by genetic traits, present in all humans, offering defense against various infectious agents.
Adaptive (acquired) immunity: Immunity obtained through other means than heredity; can be naturally acquired (developing a disease) or artificially acquired (vaccine).

Toxoids

Toxoids are normally toxic substances that have been processed to lose their toxicity.
Toxoids retain their ability to trigger the immune system to produce antibodies.
Toxoids are used in vaccines against diseases like diphtheria, tetanus, cholera.

How Antivenom is Made

Snake venom is collected.
Venom is injected into a horse to produce antibodies.
Antibodies are extracted and purified.
Purified antibodies are packaged and ready to use.

Innate and Adaptive Immunity

Innate immunity: A broad defense system against various invaders.
Adaptive immunity: A targeted immune response against specific agents like viruses or bacteria.

Adaptive Immunity

Adaptive immunity involves the production of antibodies and the activation of lymphocytes.
Lymphocytes are specific cells in the body's immune system, playing a key role in antibody and cellular responses.
Adaptive immunity is usually more effective against succeeding infections than during the initial infection.

Innate Immunity

Physical barriers: Skin and mucous membranes protect against external agents and secrete defensive molecules.
Chemical barriers: Substances in body fluids (e.g., saliva) and acidity (e.g., in the stomach) inhibit microbial growth.
Cellular defenses: Cells engulf and destroy invading organisms.
Inflammation: Redness, swelling, and fever at infection sites are responses to tissue damage or infection.
Fever: Elevated body temperature can kill invading agents and compromise their harmful effects.
Molecular defenses: Interferon and complement destroy or impedes invading microorganisms.

Physical Barriers

Skin and mucous membranes form physical barriers to prevent entry of infectious agents.
Secretions and chemicals from these surfaces (e.g., saliva, tears) destroy pathogens.

Chemical Barriers

High salt content in sweat and sebum from skin glands inhibit the growth of bacteria.
Acidic pH in the stomach inhibits the growth of certain pathogens.
Lysozyme in tears, saliva, and mucus destroys pathogens by disrupting their cell walls.

Cellular Defenses

Basophils, mast cells, eosinophils, and neutrophils are granulocytes with specific roles such as initiating inflammatory responses or combating parasites.
Neutrophils are phagocytic cells essential against infections that invade skin or mucous membranes.

Granulocytes

Basophils release histamine, initiating inflammation.
Mast cells trigger inflammation and allergies.
Eosinophils are associated with allergic reactions and fighting parasites.
Neutrophils are phagocytic cells that defend against infection.

Agranulocytes

Monocytes turn into macrophages, crucial for engulfing microbes and debris.
Lymphocytes, originating from lymphoid stem cells, contribute to adaptive immunity.
Lymphocytes circulate in blood and are found in lymph nodes, spleen, thymus, and tonsils.

Phagocytes

Phagocytes literally eat and engulf materials, like dead cells or pathogens, in body processes.
Phagocytes (like macrophages and neutrophils) patrol body tissues.
Phagocytosis: a process that involves phagocytes finding, adhering to, ingesting, and digesting microorganisms.

Inflammation

The body has a chain reaction defense process when injured or infected.
Inflammation is the body's response to tissue damage or infection, characterized by redness, heat, swelling, and pain (calor, rubor, tumor, dolor).
Certain mediators, like histamine, cause inflammation.
Pro-inflammatory mediators cause blood vessels to widen and increase blood flow

Molecular Defenses

Interferons are small protein molecules that help cells resist viral infection(s).
Other molecular defenses work as a cascade or a chain-reaction process.
The complement system is a group of proteins aiding in killing pathogens and inflammatory responses.

Natural Killer Cells

Natural killer (NK) cells are crucial for defending against infected or cancerous cells.

Complement System

The complement system is a group of about 20 proteins that enhance the immune response.
It enhances phagocytosis, directly kills pathogens, and initiates inflammatory responses.
The complement system functions as a cascade or series of reactions to amplify some effect, such as cell killing or pathogen engulfment(s).

Opsonization

Opsonins are molecules that enhance phagocytosis.
Opsonins coat pathogens, making them more readily recognized and engulfed by phagocytic cells.

Immune Cytolysis

Immune cytolysis refers to pathogen destruction by the immune system.
This is facilitated through the formation of membrane attack complexes (MAC) which cause pathogen destruction by creating holes in the pathogen membrane.

Summary

Innate and adaptive immunity are two primary defense mechanisms.
Innate immunity is rapid and non-specific, while adaptive immunity is targeted and can develop immunity.
Processes like phagocytosis, molecular defenses (e.g., interferons), and the complement system are crucial components of both systems.

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Description

Test your knowledge of key concepts in immunology, including innate and adaptive immunity, phagocytosis, and the inflammatory response. This quiz covers essential terms and components of the immune system, helping you solidify your understanding of how the body defends against infectious agents.