Biology Immunology Overview

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Questions and Answers

What is the primary function of plasma cells in the immune response?

To create immunological memory

To destroy infected cells

To activate T-cells

To produce antigen-specific antibodies (correct)

Which type of T-cell is primarily involved in activating B-cells?

T-memory cells

T-helper cells (correct)

T-effector cells

T-killer cells

What role do antigen-presenting cells (APCs) play in the immune response?

They stimulate T-killer cells

They display antigens with MHC complexes (correct)

They produce antibodies

They engulf pathogens directly

What triggers the T helper activation stage in the humoral response?

The release of chemicals by pathogens (C) Signup and view all the answers

Which of the following is NOT produced by B-cells?

T-helper cells (B) Signup and view all the answers

What is the main difference between macrophages and neutrophils during the immune response?

Macrophages prepare the way for a specific response, while neutrophils act quickly (D) Signup and view all the answers

Which cells are responsible for forming a long-term immunological memory?

B-memory cells (C) Signup and view all the answers

What is the role of cytokines in the immune response?

To activate B-cells and promote their division (B) Signup and view all the answers

What is the primary method through which artificial immunity is granted?

Immunisation by vaccines (A) Signup and view all the answers

Which of the following strategies involves making a disease disappear in a defined area while the pathogen remains present elsewhere?

Elimination of disease (A) Signup and view all the answers

What type of immunity is achieved by injecting antibodies from one individual into another?

Artificial passive immunity (D) Signup and view all the answers

Which of the following is not a method of artificial active immunity?

Oral administration of attenuated pathogens (C) Signup and view all the answers

What is the outcome of herd immunity in a population?

Decreased transmission rates of disease (B) Signup and view all the answers

What is the primary basis for the function of antibiotics?

Selective toxicity against bacteria (D) Signup and view all the answers

Which situation primarily requires ongoing immunization to prevent disease despite the presence of cases?

Elimination of the disease (B) Signup and view all the answers

What issue arises due to rapid evolution of pathogens in control measures?

Difficulty in developing effective treatments (B) Signup and view all the answers

What role do glycoproteins play in the immune response?

They help the body recognize self and non-self cells. (C) Signup and view all the answers

Which type of leukocyte is primarily involved in engulfing and digesting pathogens?

Neutrophils (B) Signup and view all the answers

Which leukocyte type is responsible for producing histamines during allergic reactions?

Basophils (A) Signup and view all the answers

What is the primary function of monocytes when they migrate into tissues?

To become macrophages and engulf pathogens. (C) Signup and view all the answers

Which of the following describes the nature of inflammation as a response to infection?

A non-specific response occurring during localized infection. (C) Signup and view all the answers

What percentage of leukocytes in the blood are typically neutrophils?

Up to 70% (B) Signup and view all the answers

Which type of leukocytes are characterized by their lack of granules and round nuclei?

Agranulocytes (A) Signup and view all the answers

Eosinophils play a significant role in which of the following conditions?

Allergic reactions and parasitic infections (D) Signup and view all the answers

What is the role of T-memory cells?

To quickly generate T-killer cells upon re-exposure to the same pathogen. (A) Signup and view all the answers

Which type of immunity involves the transfer of pre-formed antibodies from mother to fetus?

Natural passive immunity (B) Signup and view all the answers

What triggers the rapid cell division of T-killer cells?

Exposure to cytokines from activated T-helper cells. (B) Signup and view all the answers

What is the function of antibodies during the immune response?

To mark pathogens for destruction by labeling undamaged antigens. (A) Signup and view all the answers

What distinguishes natural active immunity from natural passive immunity?

Natural active immunity is acquired through direct exposure to pathogens. (D) Signup and view all the answers

What happens to the infected body cell after it presents the antigen-MHC complex?

It remains infected and becomes an antigen-presenting cell (APC). (B) Signup and view all the answers

How does a fever help combat infection?

It lowers the reproductive rate of pathogens by raising body temperature (A) Signup and view all the answers

What is a potential consequence of an untreated severe fever?

Dehydration and tissue damage (C) Signup and view all the answers

Which type of white blood cell can renew its lysosomes and digest multiple pathogens?

Macrophages (A) Signup and view all the answers

What role do interferons play in the immune response?

They inhibit viral replication and prepare neighboring cells for infection (B) Signup and view all the answers

What are antigens and their role in the specific immune response?

Unique markers on pathogens that trigger immune recognition (D) Signup and view all the answers

Which statement is true regarding neutrophils?

They die after digesting a limited number of pathogens due to lysosome depletion (C) Signup and view all the answers

What happens to capillaries during an immune response?

They dilate and become more permeable to allow leukocytes to exit (B) Signup and view all the answers

What is the primary action of bacteriostatic antibiotics?

They inhibit the growth of microorganisms. (A) Signup and view all the answers

Which of the following best describes the action of bactericidal antibiotics?

They lead to the destruction of bacterial cells. (B) Signup and view all the answers

What distinguishes broad-spectrum antibiotics from narrow-spectrum antibiotics?

Narrow-spectrum antibiotics target a limited range of pathogens. (B) Signup and view all the answers

Which of the following factors affects the effectiveness of antibiotics?

Concentration of the drug around the infected area. (B) Signup and view all the answers

What does it mean when a pathogen is said to be 'antibiotic resistant'?

The pathogen has survived an antibiotic treatment and can resist it in the future. (C) Signup and view all the answers

Which statement is true about the relationship between antibiotics and bacteria?

Antibiotic effectiveness depends on the presence of a binding site and a target metabolic pathway. (D) Signup and view all the answers

How can the emergence of 'superbugs' be primarily attributed?

Overuse of antibiotics leading to selective pressures. (B) Signup and view all the answers

To reduce the selection pressures that lead to antibiotic resistance, what should be done?

Use antibiotics only when strictly necessary. (B) Signup and view all the answers

Study Notes

Non-Specific Responses to Infection

Cell Recognition: The body's ability to distinguish between "self" and "non-self" cells is crucial for preventing illness. Cells of different organisms have unique proteins, like glycoproteins in cell membranes, that help with recognition.
Leucocytes and Types: These cells, formed in bone marrow, defend against infection. They can change shape to squeeze through blood vessels. Some have granules (granulocytes), including neutrophils (most common, engulf and digest pathogens), eosinophils (fight parasites, involved in inflammation), and basophils (produce histamines, involved in inflammation). Others lack granules (agranulocytes), like monocytes that mature into macrophages which engulf and destroy pathogens through phagocytosis, and lymphocytes which are involved in specific responses.

Non-Specific Responses

Inflammation: A localized response to infection, characterized by heat, redness, swelling, and pain. Mast cells release histamines causing blood vessels to dilate, allowing more blood flow to the infected area.
Fever: The body raises its temperature to slow pathogen reproduction. Many pathogens reproduce faster at normal body temperatures. A higher temperature helps specific immune responses function more effectively.
Phagocytosis: Cells (like neutrophils and macrophages) engulf and destroy pathogens. Lysosomes are key for breaking down pathogens.

Interferons

Interferons: Cells invaded by viruses release chemicals called interferons that block viral replication in other cells. This hinders virus reproduction. Interferons diffuse to other cells, rendering them resistant to infection.

Specific Immune Response

The main types of lymphocytes*
B-cells: Produced in bone marrow; produce antibodies (immunoglobulins) that recognize and bind to specific pathogens. When bound to an antigen, B-cells create plasma cells to produce antibodies, and B-memory cells which provide immunological memory.
T-cells: Produced in bone marrow, activated in thymus gland. They have receptors that bind to antigens on body cells. This allows them to identify infected cells, cancer cells, or cells that pose threats to body tissue. T-killer cells destroy infected cells, releasing chemicals to trigger cell death. T-helper cells activate other immune cells (other T-cells, B-cells), leading to an effective immune response, and T-memory cells give lasting immunological memory to the body.

The Humoral Response

Helper T-cell Activation: When pathogens enter the body, phagocytes attract T-helper cells. Macrophages engulf pathogens, and display/combine the antigen with MHC molecules, presenting the complex on the outer membrane. T-cells receptors bind to the complex activating the immune system. This creates clones of active T-helper cells + T-memory cells, granting long-lasting immunological memory, which produce immunoglobulins (antibodies).
Effector Stage: The antigens from the pathogen are seen by the cells through MHC receptors. The T-helper cells initiate the formation of plasma cells by B-cells, which synthesize and release large quantities of antibodies. The antibodies bind to the pathogen which labels it for phagocytosis and elimination.

The Cell-mediated Response

Cell-mediated Response: Involves T-killer cells which act on infected body cells. By identifying infected cells, T-killer cells and releasing enzymes will destroy infected body cells which limits the spread of harmful pathogens.

Primary and Secondary Immune Response

Primary Response: The body's initial response to an infection involving a pathogen take a relatively longer period of time.
Secondary Response: The body's faster response to the same pathogen in a subsequent infection. Immune cells "remember" the pathogen, making the response quicker and more effective. This involves the creation of T-memory and B-memory cells.

Developing Immunity

Natural Immunity: Natural active immunity is when the body encounters a pathogen and activates its immune response. Natural passive immunity involves receiving antibodies from another source, like a mother to a fetus through the placenta, or through breastfeeding.
Artificial Immunity: Artificial active immunity involves exposure to a safer form of the pathogen (e.g., vaccines). Artificial passive immunity involves receiving antibodies from another source (e.g., antibodies from blood serum).

Eradication, Elimination, and Control of Disease

Eradication: The complete removal of a disease from the population, eliminating it from all environments.
Elimination: Similar to eradication, but is not possible to remove completely from all environments.
Control: Reducing the incidence of disease to acceptable levels.

Herd Immunity

Herd Immunity: Occurs when a large percentage of a population is vaccinated. It offers protection to individuals who cannot be vaccinated.

Antibiotics

Antibiotic Action: Antibiotics have two effects; bacteriostatic agents stop the growth of bacteria, while bactericidal agents kill bacteria.
Antibiotic Resistance: Bacteria can develop resistance to antibiotics through mutations. This results from overuse and inappropriate use of antibiotics.

Antibiotic resistance

Factors influencing antibiotic effectiveness: The concentration of the drug around infected areas, pH, host and pathogen cell, and the susceptibility of the pathogen to the antibiotic used.
Antibiotic resistance: Occurs when pathogens develop resistance to the antibiotics that were used to treat the pathogen, and therefore the drug is ineffective.

Hospital-acquired Infections (HAIs)

Causes & prevention: HAIs are infections acquired in hospitals. Prevention involves hand hygiene, isolation of infected patients, controlling the use of antibiotics and monitoring for HAIs.

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Description

Explore the non-specific responses to infection, focusing on cell recognition and the role of leucocytes. Understand the differences between granulocytes and agranulocytes, as well as the process of inflammation. This quiz covers essential concepts in immunology essential for biology courses.