Review

Question 1

Primary lymphoid tissue

Answer 1

1. Thymus = T cells
2. Bone Marrow = B cells

Question 2

T cell “education” in Thymus

Answer 2

• immature T cells enter cortex and undergo proliferation + development
• positive selection = TCR must bind self-MHC
• negative selection = eliminate T cells that have too strong affinity for MHC

Question 3

B cell “education” in bone marrow

Answer 3

• B cells originate and develop in bone marrow
• positive selection: BCR must bind ligand
• negative selection: eliminate B cells that have too strong affinity for ligand

Question 4

Lymph nodes

Answer 4

• located along lymph vessels
• traps antigens originating in tissues and facilitate immune response

Question 5

Differentiate primary vs secondary follicles

Answer 5

Primary:
- clusters of resting B cells and some dendritic cells

Secondary:
- B cells respond to antigen (Germinal Centre)
- surrounded by resting B cells, Th cells, macrophages and dendritic cells

Question 6

High Endothelial cells

Answer 6

• specialized endothelial cells that are cuboidal or columnar Venules (HEVs) shaped
• allow activated T and B cells to enter lymph via diapedesis

Question 7

Spleen

Answer 7

• traps antigen from blood stream and facilitates immune response

Red pulp:
- rich in RBC and macrophages
- old RBC and blood-borne pathogens are removed by phagocytosis

White pulp:
- PALS (T cells surrounding arterioles)
- marginal zone rich in lymphocytes and macrophages (in between red pulp and white pulp)

Question 8

Peyer’s patches

Answer 8

• located in submucosa of small intestine
• contain primary and secondary follicles
• M cells: transfer antigen from lumen to T cells, B cells, and macrophages

Question 9

WIP Innate Imunity: Defensive Barriers (6)

Answer 9

1. Skin:
- physical barrier; sebum to trap microbes; normal flora to compete with pathogens
2. Mucus membranes:
- physical barrier traps

Question 10

How is recognition of self vs non-self achieved ?

A). B cell activation in the thymus
B). Self presentation of antigen by B cells
C). Exposure of B cells to self antigens in the thymus
D). Exposure of T cells to self antigens in the thymus

Answer 10

D). Exposure of T cells to self antigens in the thymus

Question 11

What results in a Th2 response (compared to a Th1 response)?

a). promotion of phagocytosis and IL-2 production
b). TNF and Interferon gamma production
c). strong cellular response including granulocyte activiation
d). antibody production (including IgE) and inhibition of phagocytois

Answer 11

d). antibody production (including IgE) and inhibition of phagocytois

Question 12

Which type of antigen can B cells effectively create antibodies without T cell help?

a). lipid
b). protein
c). nucleic acid
d). carbohydrate

Answer 12

d). carbohydrate
- T-independent antigens, such as those found on bacterial cell walls (LPS)

Question 13

Which of the following mechanisms is used by NK cells?

a). release of histamines
b). granzyme release
c). recognition of antigen through MHC Class 2
d). phagocytosis

Answer 13

b). granzyme release

Question 14

Which cells are most efficient at presenting antigen to T cells?

a). epithelial cells
b). NK cells
c). neutrophils
d). dendritic cells

Answer 14

d). dendritic cells

Question 15

Which complement component is responsibe for neutrophil activation and vasodilation?

a). C5a
b). C4b2a
c). C3b
d). C5b-9

Answer 15

a). C5a