Unit 4 - Immune System PART H & I

Question 1

Adaptive Immunity is the…

Answer 1

Second line of defense after innate response

Highly specific

Provides long lasting resistance to pathogens.

Two processes:

Question 2

Describe how Adaptive Immunity is highly specific

Answer 2

• recognizes specific PATHOGEN and intiates a unique response to it.
• Depends on ability of T-cells, B-cells and antibodies to bind to (i.e. recognize) specific EPITOPES on ANTIGENS.

Question 3

Describe how Adaptive Immunity provides long lasting resistance to pathogens.

Answer 3

antibodies and memory cells “remember” (i.e. have receptors for) the EPITOPES/ANTIGENS of pathogens they have encountered, and so are easily recruited upon subsequent infections.

Question 4

Describe the Adaptive Immunity’s two processes:

Answer 4

1. Cell-mediated immunity

2. Humoral (antibody mediated) immunity

Question 5

Pathogen =

Answer 5

infectious agents that cause disease

Question 6

Antigen =

Answer 6

any molecule that the body does NOT recognize as self (e.g. protein components of pathogen cell membrane/cell wall)

Question 7

Epitope =

Answer 7

part of antigen that interacts with receptors on T lymphocytes, B-lymphocytes, and antibodies.

Question 8

Adaptive Immunity - Cells

Answer 8

1. T-lymphocytes

2. B-lymphocytes (B-cells)

Question 9

Adaptive Immunity

1. T-lymphocytes

Answer 9

a. Helper T cells (TH, also known as CD4+ cells)
i. Type 1 Helper T cells (TH-1 cells)
i. Type 2 Helper T cells (TH-2 cells)

b. Cytotoxic T cells (TC, also known as CD8+ cells)
c. Regulatory T cells (Treg)

Question 10

Adaptive Immunity

1. T-lymphocytes
   a. Helper T cells (TH, also known as CD4+ cells)

Answer 10

direct/mediate adaptive immunity

• during embryonic dev., this 1 set of immature lymphocyte precursor cells (T cells), migrates from the bone marrow to the thymus gland, where they mature

Question 11

Adaptive Immunity

1. T-lymphocytes
   a. Helper T cells (TH, also known as CD4+ cells)
   i. Type 1 Helper T cells (TH-1 cells)

Answer 11

secrete INF-g (interferon-gamma) and IL-2 that activate macrophages and cytotoxic T-cells respectively.

mediate cell-mediated immunity

Question 12

Activated T lymphocytes…

Answer 12

attack & destroy virus-infected cells & help regulate other immune cells

Question 13

Adaptive Immunity

1. T-lymphocytes
   a. Helper T cells (TH, also known as CD4+ cells)
   i. Type 2 Helper T cells (TH-2 cells)

Answer 13

secrete IL-4, IL-5, IL-6 that help activate B cell growth, differentiation and antibody production.

mediate Humoral (antibody-mediated) immunity

Question 14

Cytotoxic T cells (TC, also known as CD8+ cells)

Answer 14

• role: defend the body against intracellular pathogens
• responsible for CELL-MEDIATED IMMUNITY when they attack & destroy cells that destroy cells that display MHC-I antigen complexes
• prevents the reproduction of intracellular invaders such as viruses, some parasites, & some bacteria

Question 15

Adaptive Immunity

1. T-lymphocytes
   b. Cytotoxic T cells (TC, also known as CD8+ cells)

Answer 15

Once activated, attack and destroy virus infected cells that have the specific antigen

Cause apoptosis of infected host/target cells by: release of cytotoxic (pore-forming) molecules (PERFORINS and GRANZYMES); and by activating FAS a death receptor protein on the host cell)

Question 16

Granzymes

Answer 16

activate an enzyme cascade that induces the cell to commit suicide (apoptosis)

Question 17

Adaptive Immunity

1. T-lymphocytes
   c. Regulatory T cells (Treg)

Answer 17

prevent excessive immune responses by suppressing other lymphocytes

• (DON’T directly attack pathogens & infected cells & they also bind to MHC-I complexes (like helper T cells)

Question 18

Adaptive Immunity

2. B-lymphocytes (B-cells)

Answer 18

responsible for creating humoral immunity

Naïve cells are exposed to antigen creating a primary
immune response, and then upon future exposures to the
same antigen, secondary responses occur

after activation by TH-2 cells and clonal expansion, will
develop into:
a. Plasma cells (effector cells)
b. Memory B Cells

Question 19

Adaptive Immunity

2. B-lymphocytes (B-cells)

After activation by TH-2 cells and clonal expansion, will
develop into:

Answer 19

a. Plasma cells (effector cells)
- cells that produce antibodies (from their B-cell receptors,
BCRs).

b. Memory B Cells
- long lived cells that enter circulation
- allow for a more rapid response to a secondary infection (memory B cells have B-cell receptors that can bind to antigen, stimulating the production of antibodies more directly)

Question 20

Adaptive Immunity

2. B-lymphocytes (B-cells)
   a. Plasma cells (effector cells)

Answer 20

cells that produce antibodies (from their B-cell receptors,

BCRs).

Question 21

Adaptive Immunity

2. B-lymphocytes (B-cells)
   b. Memory B Cells

Answer 21

long lived cells that enter circulation

allow for a more rapid response to a secondary infection
(memory B cells have B-cell receptors that can bind to
antigen, stimulating the production of antibodies more
directly)

Question 22

Antibody

Answer 22

describes what the molecules do: work against foreign bodies (antigens)
- also called IMMUNOGLOBINS –> describe what the molecules are: globular proteins that participate in the adaptive immune response