Adaptive Immunity: An Introduction

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Questions and Answers

Which type of immunity primarily involves T cells and is mainly responsible for defending against intracellular pathogens?

Cell mediated immunity (correct)

Humoral immunity

Passive immunity

Innate immunity

What is the primary role of antigen presenting cells (APCs) in the adaptive immune response?

To process and present antigens to T cells (correct)

To destroy pathogens directly

To increase the production of B cells

To produce antibodies against antigens

Which characteristic of adaptive immunity involves the generation of a tailored response following exposure to a specific pathogen?

Clonal expansion

Specificity (correct)

Memory

Robust response

Which of the following statements accurately describes a T cell receptor?

It can only bind to antigens presented by APCs Signup and view all the answers

If a pathogen evades the humoral immune response, which component of the adaptive immune system would primarily be involved in addressing the intracellular threat?

Cytotoxic T cells Signup and view all the answers

What is a primary function of the adaptive immune system?

Long-lasting immunity and memory. Signup and view all the answers

Which of the following correctly distinguishes a component of the adaptive immune system from the innate immune system?

Adaptive immunity is slower to activate than innate immunity. Signup and view all the answers

Which type of immunity is primarily mediated by B cells?

Humoral immunity. Signup and view all the answers

Which of the following statements regarding cytokines and their roles is true?

Cytokines help in regulation of immune responses. Signup and view all the answers

What is the role of the complement system in the adaptive immune response?

Opsonization and tagging pathogens for destruction. Signup and view all the answers

Which component is NOT typically considered part of the adaptive immune system?

Macrophages. Signup and view all the answers

How do mechanical barriers contribute to the innate immune system?

By forming physical obstructive layers against pathogens. Signup and view all the answers

Which type of immune response is characterized by the production of memory cells?

Adaptive immune response. Signup and view all the answers

What triggers a lichenoid reaction in hyperplasia?

Idiopathic causes Signup and view all the answers

Which process is primarily involved in the mechanism of action of pemphigus vulgaris?

Autoantibodies production Signup and view all the answers

Which type of immune response is primarily involved in Sjogren's syndrome?

Both humoral and cellular Signup and view all the answers

What do epithelial cells express in response to antigenic challenge in hyperplasia?

ICAM-1 Signup and view all the answers

Which of the following is NOT a characteristic of the cellular response in pemphigus vulgaris?

Increased macrophage activity Signup and view all the answers

Which cytokine-related mechanism is most directly associated with hyperplasia?

Cytokine release due to T cell chemotaxis Signup and view all the answers

What type of immune cells are the major effectors in the humoral immune response?

Plasma cells Signup and view all the answers

Which factor is involved in the tissue destruction process during hyperplasia?

Liquefactive degeneration Signup and view all the answers

What is the result of the removal of the offending material in a lichenoid reaction?

Resolution of the reaction Signup and view all the answers

Which two types of pathogenic responses initiate a cell-mediated immune response?

Cancer cells and virus-infected cells Signup and view all the answers

Which of the following is NOT a characteristic of the innate immune system?

Specificity to pathogens Signup and view all the answers

Which effector cell is primarily responsible for antigen presentation in the immune response?

Macrophage Signup and view all the answers

What is the main function of interferon gamma (IFNγ) in the immune system?

Activates macrophages and NK cells Signup and view all the answers

Why is the adaptive immune system considered specific?

It generates a unique response to each pathogen. Signup and view all the answers

Which type of cell is primarily involved in the early stages of inflammation?

Neutrophils Signup and view all the answers

What distinguishes adaptive immunity from innate immunity?

Adaptive immunity is choreographed and specific. Signup and view all the answers

Which immune cell is specifically involved in the response to parasitic infections?

Eosinophils Signup and view all the answers

Which of the following cells is NOT part of the innate immune system?

B lymphocytes Signup and view all the answers

What is the primary role of mast cells in the immune system?

Release inflammatory mediators Signup and view all the answers

Where are adaptive immune cells primarily activated?

In the lymph nodes and spleen Signup and view all the answers

What is the primary role of keeping T and B cells apart in the lymph nodes?

To minimize inappropriate activation Signup and view all the answers

Which characteristic of the adaptive immune system allows it to respond specifically to distinct antigens?

Specificity Signup and view all the answers

What process follows primary exposure to an antigen, resulting in faster responses upon re-exposure?

Memory formation Signup and view all the answers

What characterizes the diversity of the adaptive immune system?

Ability to recognize a vast variety of antigens Signup and view all the answers

Which statement describes the function of non-reactivity to self in the immune system?

Prevents injury to the host by the immune system Signup and view all the answers

What is the significance of specialisation within the adaptive immune system?

It generates responses optimal for different organisms Signup and view all the answers

In which phase does the immune system take approximately 10 days to respond to a pathogen?

Primary exposure phase Signup and view all the answers

What happens to the immune response upon resolution of an infection?

It switches off Signup and view all the answers

What aspect of the adaptive immune system is directly responsible for increasing lymphocyte populations specific to a pathogen?

Clonal expansion Signup and view all the answers

Which of the following correctly identifies the relationship between T cells and B cells within the lymph nodes?

They are kept apart to prevent activation Signup and view all the answers

Study Notes

Learning Objectives

Describe cellular and soluble components of the adaptive immune system.
Discuss the key functions of the adaptive immune system.
Distinguish between humoral and cell-mediated immunity.
Compare and contrast innate and adaptive immunity.

Innate Immunity Overview

Mechanical barriers include:
- Epithelial layers: block microbial entry.
- Enzymes/low pH: degrade microbial structures.
- Commensal microbes: compete with pathogens.
Circulating effector proteins include:
- Cytokines: regulate immune cell activities and responses.
- Complement: involved in opsonization, neutralization, coagulation, and membrane attack complex formation.
- C-reactive protein: aids in opsonization and complement activation.
Key inflammatory cytokines:
- TNFα: stimulates inflammation and activates neutrophils.
- IL-1β: activates endothelial cells and promotes coagulation.
- IFNγ: essential for anti-viral responses and activating macrophages.
- IL-8: attracts neutrophils during inflammation.
Effector cells' functions include:
- Macrophages: phagocytosis and antigen presentation.
- Neutrophils: respond quickly to inflammation.
- Dendritic cells: present antigens and produce cytokines.
- NK cells: identify and kill infected or tumor cells.
- Eosinophils and basophils: granular release for anti-parasitic responses.
- Mast cells: release histamine, a potent inflammatory mediator.

Adaptive Immunity Concepts

Adaptive immunity is specific, robust, and adapts to fight distinct antigens.
Distinction between innate and adaptive immunity:
- Innate immunity provides immediate, non-specific defense.
- Adaptive immunity provides tailored, specific immune responses.
Components of the adaptive immune system:
- T cells and B cells are housed in lymph nodes and spleen to minimize inappropriate activation.
- Key characteristics include:
  - Specificity: distinct responses for different antigens.
  - Diversity: recognition of a vast array of antigens.
  - Memory: rapid responses upon re-exposure to the same antigen.
  - Clonal expansion: proliferation of pathogen-specific lymphocytes.
  - Specialization: optimal responses against various pathogens.
  - Non-reactivity to self: prevention of damage to host tissues.

Types of Adaptive Immune Responses

Adaptive immunity consists of:
- Humoral immunity: mediated by B cells and antibodies, effective against extracellular pathogens.
- Cell-mediated immunity: realized through T cells, targeting intracellular pathogens.

Summary of Key Points

Essential characteristics of adaptive immunity:
- Specificity, memory, clonal expansion, robust responses, primary and secondary response phases.
Main components of adaptive immunity:
- B cells, T cells, antibodies, and cytokines.
Adaptive immunity acts as the final defense line against pathogens.

Additional Information

Definitions of key terms:
- Antigen: substance initiating an immune response.
- Antigen-presenting cells (APCs): process and present antigens to lymphocytes.
- B cell receptor: membrane-bound antibody on B cells.
- T cell receptor: recognizes antigens presented by APCs; involves T helper and cytotoxic T cells.

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Description

This quiz covers the fundamental concepts of adaptive immunity, including its cellular and soluble components. It aims to differentiate between humoral and cell-mediated immunity and to compare adaptive immunity with innate immunity. Perfect for students preparing for advanced study in immunology.