Adaptive Immunity: Definition, Components, and Mechanisms

Question 1

Which of the following is NOT a mechanism that contributes to immune tolerance?

Accepted Answer

Positive selection

Answer

Clonal deletion

Answer

Clonal anergy

Answer

Immune ignorance

Question 2

Which cell type presents antigens to T cells, initiating an immune response?

Accepted Answer

Dendritic cells

Answer

Macrophages

Answer

Neutrophils

Answer

Basophils

Question 3

What is the primary function of MHC class II molecules on antigen-presenting cells?

Accepted Answer

Present antigens to CD4+ T cells

Answer

Present antigens to CD8+ T cells

Answer

Bind to antibodies

Answer

Activate B cells

Question 4

Which type of T cell directly kills infected cells, playing a crucial role in cell-mediated immunity?

Accepted Answer

Cytotoxic T cell

Answer

Helper T cell

Answer

Suppressor T cell

Answer

Regulatory T cell

Question 5

What is the name of the antibody produced by plasma cells, which are differentiated B cells?

Accepted Answer

Immunoglobulin

Answer

Interferon

Answer

Cytokine

Answer

Histamine

Question 6

Which of the following is a key characteristic of immunological memory, enabling a rapid and effective response to previously encountered pathogens?

Accepted Answer

Rapid response to previously encountered antigens

Answer

Specificity for a single antigen

Answer

Suppression of immune responses

Answer

Dependence on continuous antigen exposure

Question 7

What is the primary mechanism of action of immunosuppressive drugs, which are used to prevent rejection in organ transplantation?

Accepted Answer

Inhibition of T cell activation

Answer

Stimulation of antibody production

Answer

Enhancement of phagocytosis

Answer

Promotion of inflammation

Question 8

Which type of hypersensitivity reaction is characterized by an immediate response involving the release of histamine and other inflammatory mediators?

Accepted Answer

Type I (immediate)

Answer

Type II (antibody-mediated)

Answer

Type III (immune complex)

Answer

Type IV (delayed)

Question 9

What is a key function of the complement system in immunity?

Accepted Answer

Opsonization of pathogens, enhancing phagocytosis

Answer

Activation of mast cells

Answer

Production of antibodies

Answer

Suppression of inflammation

Question 10

Which of the following is a characteristic feature of innate immunity, providing a rapid and non-specific response to infection?

Accepted Answer

Rapid and non-specific response

Answer

Specificity for a wide range of pathogens

Answer

Long-lasting memory

Answer

Dependence on prior exposure to antigens

Question 11

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

Accepted Answer

Cell communication and regulation

Answer

Antigen recognition

Answer

Antibody production

Answer

Phagocytosis

Question 12

Which of the following is the primary function of Major Histocompatibility Complex (MHC) molecules in adaptive immunity?

Accepted Answer

Presenting antigens to T cells

Answer

Producing antibodies

Answer

Activating B cells

Answer

Killing infected cells

Question 13

What is the main role of helper T cells (Th cells) in adaptive immunity?

Accepted Answer

Providing help signals for B cell activation

Answer

Killing infected cells directly

Answer

Recognizing and binding to antigens

Answer

Secreting antibodies

Question 14

Which antibody is responsible for immediate immune responses and degranulation of mast cells?

Accepted Answer

IgE

Answer

IgG

Answer

IgA

Answer

IgM

Question 15

What is the term for the process in which B cells undergo clonal expansion and differentiate into antibody-producing plasma cells?

Accepted Answer

Germinal center reaction

Answer

Somatic hypermutation

Answer

Class switching

Answer

Affinity maturation

Question 16

What is the fundamental difference between innate and adaptive immunity?

Accepted Answer

Adaptive immunity is antigen-specific, while innate immunity is not

Answer

Innate immunity is antigen-specific, while adaptive immunity is not

Answer

Innate immunity is slower than adaptive immunity

Answer

Adaptive immunity is more effective than innate immunity

Question 17

Which of the following is a major histocompatibility complex (MHC) class II gene?

Accepted Answer

HLA-DR

Answer

IL-2

Answer

TNF-α

Answer

IFN-γ

Question 18

Which cell type is primarily responsible for presenting antigens to T cells?

Accepted Answer

Antigen-presenting cell (APC), such as dendritic cells and macrophages

Answer

T cell

Answer

B cell

Answer

Neutrophil

Question 19

What is the main function of cytotoxic T cells (CD8+ T cells)?

Accepted Answer

Killing infected or cancerous cells

Answer

Releasing cytokines

Answer

Producing antibodies

Answer

Helping B cells differentiate into plasma cells

Question 20

Which class of antibody is primarily responsible for triggering the classical complement pathway?

Accepted Answer

IgM

Answer

IgA

Answer

IgE

Answer

IgG

Question 21

What is the primary function of the germinal center in adaptive immunity?

Accepted Answer

Site of affinity maturation and memory B cell generation

Answer

Site of initial T cell-B cell interaction

Answer

Site of antibody production

Answer

Site of macrophage activation

Question 22

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

Accepted Answer

Immediate response

Answer

Specificity

Answer

Memory

Answer

Clonal expansion

Question 23

Which of the following cells is involved in both innate and adaptive immunity?

Accepted Answer

Macrophage

Answer

Neutrophil

Answer

Plasma cell

Answer

T cell

Question 24

What is the key difference between a primary and a secondary immune response?

Accepted Answer

The secondary response is faster and stronger due to memory cells.

Answer

The primary response is specific for a wider range of antigens.

Answer

The secondary response produces a different class of antibodies.

Answer

The secondary response involves only B cells.

Question 25

Which cytokine is essential for the activation and proliferation of T cells?

Accepted Answer

Interleukin-2 (IL-2)

Answer

Transforming growth factor (TGF-β)

Answer

Interferon-gamma (IFN-γ)

Answer

Tumor necrosis factor (TNF)

Question 26

What is the primary function of antibody opsonization in adaptive immunity?

Accepted Answer

To enhance phagocytosis of pathogens by immune cells

Answer

To neutralize toxins

Answer

To activate complement

Answer

To stimulate B cell proliferation