Immunology Quiz: Lymphoid Organs and Antibodies

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Questions and Answers

Which of the following cells does NOT mature primarily in the bone marrow?

Basophils

Neutrophils

Eosinophils

T lymphocytes (correct)

What is the main role of costimulators in T cell activation?

To act as a checkpoint ensuring T cell activation only occurs in the presence of a genuine threat. (correct)

To provide the initial signal for T cell activation, recognizing specific antigens.

To induce the production of cytokines by macrophages.

To activate B cells to produce antibodies.

Which of the following is NOT a primary lymphoid organ?

Bone marrow

Spleen (correct)

Thymus

Fetal liver

Which of the following is NOT a major function of antibodies?

Direct destruction of antigens (D) Signup and view all the answers

What is the main function of the thymus gland?

Maturation of T lymphocytes. (D) Signup and view all the answers

Which of these immunoglobulin classes is primarily involved in antibody-dependent cellular cytotoxicity (ADCC) mediated by NK cells?

IgG (A) Signup and view all the answers

Why is the thymus considered a vestigial organ in adults?

It becomes inactive due to aging and no longer plays a significant role in immunity. (B) Signup and view all the answers

During a humoral immune response, which part of the antibody molecule remains constant while the heavy chain region might change?

Variable region of the light chain (D) Signup and view all the answers

Which immunoglobulin class is responsible for stimulating mast cells and eosinophils, leading to the release of inflammatory mediators?

IgE (B) Signup and view all the answers

What does the term 'hemopoietic progenitor cells' refer to?

Cells that can differentiate into all types of blood cells. (B) Signup and view all the answers

What is the primary difference between the primary and secondary humoral immune responses?

The speed and magnitude of the response (A) Signup and view all the answers

What is the function of the spleen in the immune system?

Filter blood and remove old or damaged red blood cells. (A) Signup and view all the answers

Which of the following is NOT a typical characteristic of the maturation process of T lymphocytes in the thymus?

Selection for self-reactive T cells. (A) Signup and view all the answers

What happens to the majority of T lymphocytes that enter the thymus?

They degenerate and are not released into the bloodstream. (B) Signup and view all the answers

Which of these is NOT a component of the complement cascade?

Histamine release (B) Signup and view all the answers

What is the function of MHC molecules in the immune system?

Presenting antigens to immune cells (D) Signup and view all the answers

How do antibodies contribute to opsonization?

By binding to the pathogen surface, making it easier for phagocytosis (C) Signup and view all the answers

Which of the following statements accurately describes the role of leukocytes in the immune system?

Leukocytes are critical for both innate and adaptive immune responses (B) Signup and view all the answers

Based on the information provided, which type of leukocyte is an exception to the general rule of maturation in the blood?

T lymphocytes (C) Signup and view all the answers

What is the primary mechanism by which complement activation contributes to immune defense?

Triggering cell lysis, opsonization, and immune cell recruitment (A) Signup and view all the answers

Which of the following statements is TRUE about the relationship between antibodies and immunoglobulins?

Antibodies and immunoglobulins are different terms for the same protein (B) Signup and view all the answers

What is the main role of the variable domain in an antibody's structure?

To serve as the antigen-binding site (B) Signup and view all the answers

Which component of the antibody structure contains the most amino acids?

The heavy chain (C) Signup and view all the answers

How many light chains are present in a typical antibody monomer?

Two (C) Signup and view all the answers

What type of bonds link the polypeptide chains in an antibody?

Disulfide bonds (C) Signup and view all the answers

Which part of the antibody determines its classification into different classes?

Structure of the constant domains (B) Signup and view all the answers

What is formed when two heavy chains of an antibody are attached to each other?

A Y-shaped molecule (A) Signup and view all the answers

What feature differentiates the light chains from the heavy chains in structure?

Light chains have variable and constant domains (C) Signup and view all the answers

In an antibody, which domain is larger in size?

Heavy chain constant domain (D) Signup and view all the answers

What is the significance of the antigen-binding site in an antibody's function?

It allows the antibody to recognize and bind to specific antigens (B) Signup and view all the answers

Which type of chain is directly involved in the formation of the antigen-binding site?

Both heavy and light chains (D) Signup and view all the answers

What is the primary role of antibodies in relation to pathogens within infected cells?

They function primarily in the extracellular environment. (C) Signup and view all the answers

Which type of T lymphocyte is primarily responsible for killing infected cells directly?

Cytotoxic T lymphocytes (CD8 cells) (B) Signup and view all the answers

How do infected cells communicate their infection status to the immune system?

By presenting processed protein fragments on their surface. (A) Signup and view all the answers

What role do helper T lymphocytes (CD4 cells) play in immune response?

They activate other immune cells and coordinate the immune response. (A) Signup and view all the answers

What process prepares antigens for destruction by innate immunity?

Opsonization (A) Signup and view all the answers

Which cells are primarily responsible for recognizing foreign antigens displayed on infected cells?

Cytotoxic T lymphocytes (CD8 cells) (B) Signup and view all the answers

What is an incorrect statement regarding the function of antibodies?

They are capable of directly killing infected cells. (C) Signup and view all the answers

Which immune cells are NOT involved in directing the activities of the immune response?

Neutrophils (C) Signup and view all the answers

What best describes the function of opsonization in the immune response?

It enhances the recognition and phagocytosis of pathogens. (D) Signup and view all the answers

Which of the following cells does NOT belong to the adaptive immune system?

Natural killer cells (A) Signup and view all the answers

Study Notes

Learning Objectives

Define all terms listed in the Definitions section (page 2).
Understand the adaptive immune response's key properties.
Compare and contrast humoral and cell-mediated adaptive immunity, identifying the involved cells.
Define antigen and antigenic determinant.
Compare and contrast Class I and Class II MHC/HLA molecule cellular expression and function.
Describe antigen-presenting cell function and the cell types that act as APCs.
Define self-tolerance and immunocompetence.
Define clonal selection.
Illustrate antibody structure, including heavy and light chains, variable and constant domains, Fab and Fc regions.
Define antibody affinity and avidity.
Differentiate between five antibody (immunoglobulin) classes.
List and describe antibody effector functions.
Compare and contrast B cell activation in primary and secondary immune responses.
Describe the role of immunological memory in both responses.
Differentiate between CD4 helper T cells and CD8 cytotoxic T cells, including their functions.
Describe the process of CD4 and CD8 T cell antigen recognition.
Describe T cell activation processes.
Define costimulation.
List and describe the functions of TH1, TH2, TH17, and Treg effector CD4 T cells.
Describe T cell-mediated immunological memory.
Outline the timecourse of the immune response to an infection.
Define inflammation.
Explain immune system interactions with infection timecourses.
Describe the location and functions of Interleukin-2, CD3, CD28, CD20, CD40, PD-1, glucocorticoid, Interleukin-17, CTLA4.

Definitions (Page 2)

Immunity: The ability to resist damage from foreign substances (microorganisms, chemicals, or cancer cells).
Innate immunity: A nonspecific immune system branch responding similarly to each exposure to foreign substances.
Adaptive immunity: A specific immune system branch, responding faster and stronger each time it encounters a foreign substance.
Specificity: The ability of adaptive immunity to target a specific substance.
Diversity: The large number of lymphocytes exhibiting different antigen-specificities.
Memory: The ability of adaptive immunity to remember previous encounters with a particular substance and respond more effectively.
Antigens: Substances stimulating adaptive immunity (foreign or self-antigens).
Foreign antigens: Substances not produced by the body. Examples include pollen, animal dander, food components, and microorganisms.
Self-antigens: Molecules produced by the body potentially stimulating either beneficial or harmful responses (including tumor and autoimmune responses).
Antibodies: Proteins produced by plasma cells (differentiated B cells) in response to antigens, also known as immunoglobulins.
Opsonization: Rendering pathogens susceptible to phagocytosis via antibody or complement protein binding.
Complement: A group of ~20 proteins (~10% plasma globulin) mediating cell lysis, opsonization, and immune cell recruitment.
Major Histocompatibility Complex (MHC) molecules: Glycoproteins found on most body cells, displaying processed antigens for immune cell recognition.
Costimulator: A molecule on antigen-presenting cells, providing a second signal for naive T cell activation.
Lymphocytes: White blood cells derived from myeloid/lymphoid lineages. (Neutrophils, eosinophils, basophils, monocytes, erythrocytes, platelets).

Cells, Tissues, and Organs of the Immune System

Hematopoietic stem cells give rise to all blood cells, differentiating into myeloid and lymphoid lineages.
Myeloid lineage forms neutrophils, eosinophils, basophils, monocytes, erythrocytes, and platelets.
Lymphoid lineage forms T and B lymphocytes and natural killer (NK) cells.
Thymus gland releases hormones like thymosin, promoting T cell maturation.
Lymphoid stem cells migrate to thymus for differentiation
Spleen filters blood, removing aged erythrocytes and pathogens.
White pulp contains B and T cells, initiating an immune response.
Red pulp contains macrophages, clearing cellular debris.

Cells of Adaptive Immunity

Phagocytic cells (monocytes/macrophages): Engulf and destroy pathogens, using phagocytosis to digest ingested material within the cell's lysosomes.
Dendritic cells: Bridge between innate and adaptive immunity, acting as antigen-presenting cells (APCs) to activate T and B cells by displaying processed antigens on their surfaces to initiate an adaptive immune response.
Lymphocytes (B and T cells): Respond specifically to antigens, initiating an adaptive immune response.

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Description

Test your knowledge on immunology concepts including the roles of lymphoid organs and the functions of antibodies. This quiz covers topics such as T cell activation, the thymus gland, and different immunoglobulin classes. Perfect for students studying immunology or related biomedical fields.