chapter 18 study guide

Question 1

Characteristics of Adaptive Immunity

Answer 1

specificity

memory

Question 2

Targets specific pathogens.

Quickly responds to previously encountered pathogens.

Answer 2

Specificity:

Memory:

Question 2

Mechanism of Specificity and Memory

Answer 2

programming of immune cells

primary and secondary

Question 3

Enables rapid response to subsequent pathogen exposures.

Answer 3

programming of immune cells

Question 4

Triggered by the first exposure to a pathogen or vaccine.
:
Faster and stronger due to immune memory.
Specific to the initial pathogen.

Answer 4

primary response

secondary response

Question 5

cell types in adaptive immunity

Answer 5

b cells

t cells

Question 6

Mature in bone marrow.
Produce glycoproteins (antibodies or immunoglobulins).
Defend against extracellular pathogens and toxins.
Mechanism: Humoral immunity (involves B cells and antibodies).

Answer 6

B cells

Question 7

Mature in the thymus.
Act as central orchestrators of both innate and adaptive immune responses.
Destroy cells infected with intracellular pathogens.
Mechanism: Cell-mediated immunity (targeting and destruction of intracellular pathogens).

Answer 7

T cells

Question 8

Trigger activation of adaptive immune defenses.
Unique to specific pathogens (e.g., varicella-zoster virus antigens differ from other viral pathogens).
Differ from PAMPs (found on numerous pathogens)

Answer 8

antigen

Question 9

Found in capsules, cell walls, fimbriae, flagella, pili, toxins, and enzymes.

Answer 9

bacteria antigens

Question 10

Associated with capsids, envelopes, and spike structures.

Answer 10

viral antigens

Question 11

Effectiveness as antigens depends on structural complexity

Answer 11

proteins most effective

carbohydrates less effective

nucleic acids least effective

Question 12

Smaller exposed regions on antigen surfaces recognized by antibodies or T cells.

Answer 12

epitopes

Question 13

Small molecules (______):
Not antigenic alone.
Become antigenic when attached to larger carrier molecules (e.g., proteins).

Answer 13

haptens

Question 14

cause specific immune responses, including allergic reactions:
Example:
Urushiol (poison ivy oil) causes contact dermatitis.
Penicillin can trigger allergic reactions to its drug class.

Answer 14

haptens

Question 15

An ____ is a macromolecule that reacts with components of the immune system

Answer 15

antigen

Question 16

Also called immunoglobulins.
Glycoproteins found in blood and tissue fluids

Answer 16

antibodies

Question 17

Consists of four protein chains held together by disulfide bonds:
Disulfide bond: Covalent bond between sulfhydryl R groups of two cysteine amino acids.
Two identical heavy chains (largest).
Two identical light chains (smallest).
Forms a Y-shaped structure.

Answer 17

basic structure of antibody monomer

Question 18

Arms of the Y-shaped antibody molecule.
Serves as the site of antigen binding.

Answer 18

FAB region

Question 19

Neutralization of pathogens.
Agglutination or aggregation of pathogens.
Antibody-dependent cell-mediated cytotoxicity.

Answer 19

FAB region

Question 20

Located in the trunk of the Y.
Site of complement factor binding.
Site of binding to phagocytic cells during antibody-mediated opsonization.

Answer 20

FC region

Question 21

The _____ determines the class (isotype) of the antibody.

Answer 21

constant region

Question 22

five classes of antibodies

Answer 22

IgG, IgM, IgA, IgD, IgE.

Question 23

Penetrates tissue spaces efficiently.
Only antibody that crosses the placental barrier, providing passive immunity to the fetus.
Most versatile in defense against pathogens.

Answer 23

IgG

Question 24

First antibody produced during primary and secondary immune responses. Diagnostic marker for active/recent infections (pathogen-specific IgM). Ten Fab sites enhance pathogen binding.

Answer 24

IgM

Question 25

Most abundant in mucus secretions (protects mucous membranes). Found in breast milk, tears, and saliva. Traps pathogens in mucus for elimination.

Answer 25

IgA

Question 26

Found on B cell surfaces as an antigen-binding receptor. Function: Not secreted by B cells. Trace amounts in serum result from degradation of old B cells

Answer 26

IgD

Question 27

Involved in anti-parasitic defenses. Fc region binds to basophils and mast cells. Fab region binds antigen epitopes, triggering release of pro-inflammatory mediators. Central to allergic reactions and inflammation defense mechanisms.

Answer 27

IgE

Question 28

Antibodies involved: IgG, IgM, IgA. Mechanism: Antibodies bind to epitopes on the pathogen/toxin surface, preventing attachment to cells.

Answer 28

Neutralization

Question 28

Neutralization of pathogens. Opsonization for phagocytosis. Agglutination (aggregation of pathogens). Complement activation. Antibody-dependent cell-mediated cytotoxicity. Provide a link between adaptive specific immunity and innate nonspecific immunity.

Answer 28

Functions of antibodies

Question 29

Secretory IgA: Blocks pathogens from attaching to intestinal mucosal cells. Antibodies neutralize toxins by blocking their attachment to target cells. Viruses are neutralized, preventing infection of cells.

Answer 29

neutralization

Question 30

Pathogens are coated with molecules (e.g., complement factors, C-reactive protein, serum amyloid A) to assist phagocytosis. IgG acts as an excellent opsonin by binding Fab sites to pathogen epitopes.

Answer 30

opsonization

Question 31

Cross-linking of pathogens by antibodies creates large aggregates. IgG: Two Fab antigen-binding sites can bind two separate pathogens, clumping them together. Large aggregates are easier for kidneys and spleen to filter from blood and easier for phagocytes to ingest. IgM: Pentameric structure provides ten Fab binding sites per molecule. Most efficient antibody for ______.

Answer 31

Agglutination (Aggregation)

Question 32

Three pathways, with the _____ being the most efficient. requires: Initial binding of IgG or IgM antibodies to the surface of a pathogen. Recruitment and activation of the C1 complex.

Answer 32

classical pathway

Question 33

____ is a collection of genes coding for___ molecules on the surface of all nucleated cells. In humans, these genes are also called human leukocyte antigen (HLA) genes. Mature red blood cells lack a nucleus and do not express ___ molecules

Answer 33

MHC

Question 34

Found on all nucleated cells. Presents: Normal self-antigens. Abnormal or nonself antigens (e.g., pathogens) to effector T cells for cellular immunity.

Answer 34

MHC 1

Question 35

Found only on macrophages, dendritic cells, and B cells. Presents: Abnormal or nonself antigens for the initial activation of T cells.

Answer 35

MHC 2

Question 36

Composed of: A longer α protein chain. A smaller β2 microglobulin protein. Only the α chain spans the cytoplasmic membrane. The α chain folds into three domains: α1, α2, and α3.

Answer 36

MHC 1

Question 37

Two protein chains (α and β) of similar length. Both chains span the plasma membrane. Each chain folds into two domains: α1 and α2 (α chain). β1 and β2 (β chain).

Answer 37

MHC 2

Question 38

Formed by α1 and α2 domains. Formed by α1 and β1 domains.

Answer 38

MHC 1 MHC 2

Question 39

All nucleated cells process and present antigens with MHC molecules to signal the immune system. Macrophages, dendritic cells, and B cells specifically present antigens to activate T cells, making them ____.

Answer 39

antigen presenting cells APC

Question 40

Function as phagocytes. Ingest and kill pathogens that penetrate the skin or mucous membranes. Recognize pathogens via nonspecific receptor interactions (e.g., PAMPs, toll-like receptors, complement, or antibody receptors).

Answer 40

Macrophages and dendritic cells

Question 41

Do not function as phagocytes. Use antigen-specific immunoglobulin receptors (monomeric IgD and IgM) to interact with foreign pathogens or free antigens. Internalize antigens through endocytosis, then process and present them to T cells.

Answer 41

B cells

Question 42

Found on all normal, healthy, nucleated cells.

Answer 42

Role of MHC I in Normal Cells:

Question 43

Cross-presentation mechanisms are not fully understood but are mainly carried out by

Answer 43

dendritic cells

Question 44

Originates from hematopoietic stem cells (HSCs) in the bone marrow. Differentiates into lymphoid stem cells, then immature lymphocytes (lymphoblasts) immature T cells travel via the bloodstream to the thymus for maturation

Answer 44

T cell production

Question 45

98% of thymocytes are eliminated during thymic selection. The remaining 2% mature and exit the thymus as

Answer 45

mature naive T cells

Question 46

T cells are divided into

Answer 46

helper T cells, regulatory T cells, and cytotoxic T cells.

Question 47

Central orchestrators of immune responses. Activate and direct humoral and cellular immunity. Enhance pathogen-killing functions of macrophages and natural killer (NK) cells.

Answer 47

helper T cells cd 4

Question 48

Prevent undesirable or damaging immune responses. Role in peripheral tolerance to protect against autoimmune diseases.

Answer 48

regulatory T cells cd 4

Question 49

Effector cells for cellular immunity. Recognize and destroy cells infected by intracellular pathogens. Kill infected cells along with pathogens inside.

Answer 49

Cytotoxic T Cells (CD8+):

Question 50

Long-lived and "remember" a specific antigen/epitope. Provide a rapid and strong secondary response upon subsequent exposure.

Answer 50

memory helper T cells

Question 51

____are derived from multipotent hematopoietic stem cells (HSCs) in the bone marrow. Unlike T cells, ____ do not migrate to the thymus for maturation; they mature in the bone marrow.

Answer 51

B cells

Question 52

Ensures B cells have functional antigen-binding receptors.

Answer 52

B cell maturation process positive selection

Question 53

Removes self-reactive B cells to prevent autoimmunity through: Apoptosis (cell death). Receptor editing/modification to eliminate self-reactivity. Induction of anergy (Non responsiveness).

Answer 53

B cell maturation process negative selection

Question 54

Immature B cells that pass selection leave the bone marrow and travel to the ____ for final maturation.

Answer 54

spleen

Question 55

Mature B cells in the spleen are referred to as

Answer 55

naive mature B cells

Question 56

Individual's own adaptive immune defenses are activated. Adaptive immune defenses are transferred from another individual or animal

Answer 56

Active Immunity: passive immunity

Question 57

Develops after natural exposure to a pathogen. Examples: Lifelong immunity after recovery from chickenpox or measles

Answer 57

Natural Active Immunity

Question 58

Involves the natural transfer of antibodies from parent to child: IgG: Crosses the placenta, providing passive immunity for up to 6 months after birth. Secretory IgA: Transferred through breast milk.

Answer 58

natural passive immunity

Question 59

Transfer of antibodies from a donor to another individual for: Prophylaxis (e.g., rabies, hepatitis A/B, chickenpox in high-risk individuals). Treatment of active infections (e.g., cytomegalovirus, Ebola). Toxin-related diseases (e.g., tetanus, botulism, diphtheria). Example: 1995 Ebola outbreak, where blood transfusions from recovered patients reduced mortality

Answer 59

artificial passive immunity

Question 60

Deliberate exposure to weakened/inactivated pathogens or key pathogen antigens to activate immunity

Answer 60

vaccination artificial active immunity

Question 61

occurs when there are too few susceptible individuals in a population for a disease to spread effectively. It protects susceptible individuals indirectly, even if they cannot mount their own immune response

Answer 61

herd immunity

Question 62

benefits unvaccinated individuals if a critical percentage of the population is immune

Answer 62

herd immunity