Specific Acquired Immunity - Diebel

Question 1

T Cell Function

Answer 1

Survey the surfaces of cell’s looking for ones that have been infected
or that are dangerously changed/mutated
-CELL MEDIATED IMMUNITY

Question 2

B Cell Function

Fully differentiated=Plasma cell

Answer 2

Protects extracellular spaces of body by RELEASING ANTIBODIES into fluids

• Don’t require recognition of MHC or presentation
• HUMORAL immunity

Question 3

IgG functional properties

Answer 3

• Most abundant
• 6 IgG’s cooperate to activate COMPLEMENT –> inflammation
• some can lyse bacterium by making holes in memebrane
• ONLY Ig that passes the placenta from mother to fetus

Question 4

IgM

Answer 4

• VERY good at activating complement

- 1st antibody type to appear in blood after exposure to a new antigen (then replaced by IgG

Question 5

IgD

Answer 5

-inserted into B cell membranes as their antigen receptor.

Question 6

IgA

Answer 6

• Ig in secretions like saliva, tears, genitourinary, and intestinal fluids, milk
• associated with SECRETORY COMPONENT, which it acquires from epithelial cells during the process of being secreted.

-Secretory component makes it resistant to digestive enzymes

Question 7

IgE

Answer 7

• attaches to MAST CELLS
• When IgE finds antigen it causes mast cell to make –> prostaglandins, leukotriends, and cytokines
• —> release granules that contain histamine
• -Produce allergy symptoms
• -Real role of IgE is in resistance to parasites

Question 8

MHC I
What cells are they on?
how do they work?
What cell do they stimulate?

Answer 8

On ALL cells except RBC
-Antigen synthesized WITHIN the cell.

Infected with a virus –> Cell breaks down virus and displays it on MHC I

-CD8+ killer T cells see the display

Question 9

MHC II
What cells are they on?
how do they work?
What cell do they stimulate?

Answer 9

• on monocytes/macs, DC, B cells, and epithelial cells of thymus
• antigens are products of PHAGOCYTOSIS
• APC’s bring antigen to T or B cells and activate them?

Question 10

Th1 helper T cell:

Answer 10

1. T cell migrates to site of invasion
2. re-stimulated by local APCs and release lymphockines
3. these attract and activate monocytes and macrophages
4. ==Intense inflammation

Question 11

Cytotoxic/Killer T cells:

CD8+ response:

Answer 11

Kills cells they recognize as having abnormal molecules being displayed on MHC I

Question 12

What do all T cells express?

Answer 12

CD3 and have T cell receptors

Question 13

Th17 Helper T cells

Answer 13

• cause focused inflammation

- MORE powerful than Th1

Question 14

Th2 helper T cell

Answer 14

• Stimulate macs to become M2s.
• wall off pathogens and promote healing
• very important in PARASITE immunity

Question 15

Tfh (follicular)

Answer 15

1. stimulated by antigen
2. migrate from T cell area of lymph nodes into B cell follicles
3. BOOM! help B cells get activated
4. Also provide some instructions about what Ig the B cell should make.

Question 16

Treg (regulatory)

Answer 16

Make IL-10 cytokine that SUPPRESSES the activation/function of Th1, Th17, Th2 cells

-Keeps the immune system in check

Question 17

What cells have CD4+ molecular marker?

Answer 17

Th1, Th2, Th17, Tfh, Treg

Question 18

What molecular markers do B cells have?

Answer 18

Igs,
CD40
CD79a
CD79b

Question 19

Activation of AlphaBeta T cells?

2 steps!

Answer 19

Signal 1. TcR recognition of HLA bound antigen
-CD4+ + MHC II or CD8+ + MHC I

Signal 2: B7-1 (CD80) or B7-2 (CD86) on APC binds to T cell surface protein CD28

Other costim:

• CD2 on T cell binds to CD58
• LFA-1 on T cell binds ICAM
• cytokine signals

Question 20

General activators of T cells (cytokines)

Answer 20

IL-2 (autocrine)

IL-15

Question 21

Th0 —> Th1 cytokine stimulus?

Answer 21

IL-12 and IFN-gamma

Question 22

Th0 —-> Th2 cytokine stimulus?

Answer 22

IL-4

Question 23

Cytokines that down regulate Th1?

Th2?

Answer 23

IL-10 down regs Th1

TGF-beta down regs Th1 and Th2

Question 24

Killer T cell– Kill by FAS

Answer 24

T cell expressing FAS ligand binds to FAS protein on target cell

–> induces caspase activation and apoptosis

Question 25

Killer T cell– Kill by secreting Toxic agents

Answer 25

• Secrete TNF that can induce apoptosis.
• Secrete Perforin: pore forming protein
• Granzymes: induce apoptosis

Question 26

What pathogens are antibodies important for?

Answer 26

Extracellular!

-Staphlococcus, Streptococcus, Hemophilus

Question 27

X linked agammaglobulinemia (B)

Answer 27

Absence of B lymphocytes

Question 28

CD40 ligand deficiency (B)

Answer 28

Failure of Ig class switching

Question 29

Activation-induced Cytidine Deaminase Defiency (B)

Answer 29

Failure of Ig class switching

Question 30

Common Variable Immunodeficiency (B)

Answer 30

Failure to produce antibodies against particular antigens

Question 31

Omenn Sydnrome (B & T )

Answer 31

VDJ recombination failure.

Can’t produce BCRs or TCRs

Question 32

X-linked severe combined iummnodeficiency (T)

Answer 32

Failure to produce mature T lymphocytes

Question 33

DiGeorge Syndrome (T)

Answer 33

Failure of thymus to develop correctly

Question 34

Hemophagocytic lymphohistiocytosis (T)

Answer 34

Failure of CD8+ T cells and NK cells to produce and/or release lytic granules

Question 35

IPEX (T)

Answer 35

Failure of peripheral tolerance due to defective regulatory T cells