Lecture 11

Question 1

What is the adaptive immunity?

Answer 1

defenses that target a specific pathogen

Question 2

What is the primary and secondary response for adaptive immunity?

Answer 2

• primary: first time the immune system combats a particular foreign substance
• secondary: later interactions with the same foreign substance; faster and more effective due to memory

Question 3

What are the 2 types of immunity?

Answer 3

1) humoral immunity
2) cellular immunity (cell-mediated immunity)

Question 4

What is humoral immunity?

Answer 4

produces antibodies that combat foreign molecules (antigens)

Question 5

What are b cells? What type of immunity are they involved in?

Answer 5

• lymphocytes that are created and mature in red bone marrow
• recognize antigens and makes antibodies
• humoral immunity

Question 6

What are cytokines?

Answer 6

chemical messengers produced in response to a stimulus

Question 7

What are interleukins? (ILs)

Answer 7

cytokines between leukocytes

Question 8

What are chemokines?

Answer 8

induce migration of leukocytes

Question 9

What are interferons? (IFNs)

Answer 9

interfere with viral infections of host cells

Question 10

What are tumor necrosis factor alpha? (TNF-alpha)

Answer 10

involved in the inflammation of autoimmune diseases

Question 11

What are hematopoietic cytokines?

Answer 11

control stem cells that develop into red and white blood cells

Question 12

What does overproduction of cytokines lead to?

Answer 12

cytokine storm

Question 13

What are antigens?

Answer 13

substance that triggers an immune response by being recognized as foreign by the immune system
- substance that cause the production of antibodies

Question 14

What is an antibody?

Answer 14

protein produced by the immune system (by B cells) in response to an antigen, designed to bind to and neutralize or mark the antigen for destruction

Question 15

What do antibodies interact with?

Answer 15

epitopes, antigenic determinants
- on the antigen

Question 16

What are haptens?

Answer 16

antigens too small to provoke immune responses and attach to carrier molecules

Question 17

What are immunoglobulins? (Ig)

Answer 17

globular proteins

Question 18

What does valence mean in antibodies?

Answer 18

number of antigen-binding sites on an antibody

Question 19

What does a 4-protein antibody chain look like?

Answer 19

2 identical light chains + 2 identical heavy chains joined by disulfide links
- variable regions at the ends of the arms to bind epitopes
- constant region is the stem (identical for a particular Ig class)

Question 20

What are the characteristics of IgG?

Answer 20

• monomer
• 80% serum antibodies
• in the blood, lymph, intestine

Question 21

What are the functions of IgG?

Answer 21

• crosses the placenta
• protect the fetus
• triggers complement
• enhances phagocytosis
• neutralizes toxins and viruses

Question 22

What are the characteristics of IgM?

Answer 22

• pentamer made of five monomers held with a J chain
• 6% of serum antibodies
• remains in blood vessels
• first response to an infection, short-lived

Question 23

What is the function of IgM?

Answer 23

causes clumping of cells and viruses

Question 24

What are the characteristics of IgA?

Answer 24

• monomer in serum
• dimer in secretions
• 13% of serum antibodies
• common in mucous membranes, saliva, tears, and breast milk

Question 25

What is the function of IgA?

Answer 25

prevents microbial attachment to mucous membranes

Question 26

What are the characteristics of IgD?

Answer 26

• monomer
• 0.02% of serum antibodies
• structure similar to IgG
• in blood, in lymph, and on B cells

Question 27

What is the function of IgD?

Answer 27

• no well-defined function
• assists in the immune response on B cells

Question 28

What are the characteristics of IgE?

Answer 28

• monomer
• 0.002% of serum antibodies
• on mast cells, on basophils, in blood

Question 29

What is the function of IgE?

Answer 29

cause the release of histamines when bound to antigens
- lysis of parasitic worms

Question 30

What is the function of the major histocompatibility complex?

Answer 30

• the genes encode molecules on the cell surface
• Class 1: membrane of nucleated animal cells
• Class 2: surface of antigen-presenting cells (also B cells)

Question 31

How do antibody-producing cells go through clonal expansion?

Answer 31

• inactive b cells contain surface Ig that bind to antigen
• B cell internalizes and processes antigen
• antigen fragments are displayed on MHC class II molecules
• T helper cell contacts the displayed antigen fragment and releases cytokines that active B cells
• B cell undergoes proliferation

Question 32

What does clonal selection differentiate activated B cells into?

Answer 32

• antibody-producing plasma cells
• memory cells

Question 33

What is clonal deletion?

Answer 33

eliminates harmful B cells

Question 34

What are t-dependent antigens?

Answer 34

antigen that requires a helper-T cell to produce antibodies

Question 35

What do t-independent antigens do?

Answer 35

• stimulates B cell without the help of T cells
• provokes a weak immune response to produce IgM
• no memory cells generated

Question 36

What are the results of the antigen-antibody interaction?

Answer 36

• antigen-antibody complex forms
• protects the host by tagging foreign molecules or cells for destruction
  = agglutination
  = opsonization
  = antibody-dependent cell-mediated cytotoxicity
  = neutralization
  = activation of the complement system

Question 37

What is affinity?

Answer 37

strength of the bonds