Lecture 7 - Lymphoid anatomy

Question 1

What are the two forms of movement immune cells must undergo? [2]

Answer 1

• Movement to a tissue/organ

- Movement within a tissue/organ

Question 2

How does the immune system raise the chances that rare antigen specific T and B cells will interact with each other? [3]

Answer 2

• Have collections of T-cells and immune cells in site where infection is likely
• Have cells circulate around the body
• Have specialised sites where antigens are captured

Question 3

Where do B and T cells develop?

Answer 3

Primary lymphoid tissues

Question 4

List the two organs of the primary lymphoid system. [2]

Answer 4

• Thymus

- Bone marrow

Question 5

List the three organs of the primary lymphoid system. [3]

Answer 5

• Lymph nodes
• Spleen
• MALT

Question 6

What is in the lymphoid vessels? [3]

Answer 6

• Lymph fluid
• Lymphocytes
• Tissue dentritic cells

Question 7

What is the role of dendritic cells once they enter a lymph node?

Answer 7

They present antigens to T-cells to activate them

Question 8

What do T-cell do once they are activated?

Answer 8

Move from the lymph nodes through efferent vessels

Question 9

How long does the immune system take to adapt to a new antigen?

Answer 9

4-6 days

Question 10

What is the role of the cortex of the lymph node?

Answer 10

The main area that B-cells are found

Question 11

What is the role of the Paracortex of the lymph mode?

Answer 11

The main area that T-cells are found

Question 12

What is the role of the medulla of the lymph node?

Answer 12

Contains a mix of:

• Plasma
• T-cells
• Variety of cells such as macrophages

Question 13

What is the role of secondary follicles of the lymph node?

Answer 13

Area where B-cell proliferation is extremely high

Question 14

What happens to secondary follicles once the infection has been dealt with?

Answer 14

They turn back into primary follicles

Question 15

True or False? There is no lymph drainage into the spleen.

Answer 15

True

Question 16

How does antigen get into the spleen?

Answer 16

Through the blood

Question 17

What tissue allows lymphocytes to leave the bloodstream and enter lymph nodes?

Answer 17

The high endothelial venules

Question 18

List four types of adhesion molecules that help with lymphocyte migration. [4]

Answer 18

• Selectin
• Ig superfamily
• Integrin
• Mucin-like vasscular addressin

Question 19

What is the first process of lymphocyte migration?

Answer 19

Selectin driven Rolling

Question 20

How does selectin driven rolling work?

Answer 20

E-selectin recognises sialyl-Lewis X structures on immune cells

Question 21

What is the second process of lymphocyte migration?

Answer 21

Firm attachment

Question 22

How does firm attachment work?

Answer 22

• ICAM-1 and ICAM-2 are induced on vessels
• They bind to CR3 and LFA-1 on leukocytes
• Rolling is stopped

Question 23

What is the third process of lymphocyte migration?

Answer 23

Extravasation

Question 24

How does extravasation work?

Answer 24

• Leukocyte crosses the endothelial wall

- Involved LFA-1/CR3

Question 25

What is the role of chemokines?

Answer 25

To control the movement of cells

Question 26

Where are CXCL8 and CCL2 produced?

Answer 26

At the infection site

Question 27

What is the role of CXCL8?

Answer 27

Released by macrophages to attract neutrophils, and mobilise naive T-cells

Question 28

What is the role of CCL2?

Answer 28

Produced by epithelial cells and stromal cells and attracts monocytes