L2- Cells and Tissues of the Immune System I

Question 1

What are the differences between the roles of primary lymphoid organs compared to secondary?

Answer 1

Primary nurture lymphocyte development whereas secondary support their maturation, survival and activation

Question 2

What are some components of innate immunity?

Answer 2

Barrier tissues:
e.g. skin, mucosa
Soluble factors:
- complement
- antimicrobial peptides / enymes
Activation of effector cells
- Granulocytes (neutrophils, eosinophils, basophils)
- Monocytes/macrophages
- Dendritic cells
- NK cells

Question 3

What are PAMPs?

Answer 3

Pathogen associated molecular patterns

Question 4

Aside from potential loss of function, what are the other 4 symptoms of inflammation?

Answer 4

• Pain
• Redness
• Heat
• Swelling

Question 5

Describe what happens during inflammation

Answer 5

• Increase vascular diameter
• Cells lining blood vessels express cell-adhesion molecules
• Effector cells are recruited
• Blood vessels become more permeable
• Clotting

Question 6

What are granulocytes and the three types?

Answer 6

A white blood cell with secretory granules in its cytoplasm

• Neutrophils
• Eosinophils
• Basophils

Question 7

What are some properties of neutrophils?

Answer 7

• Most abundant leukocyte (50-70%)
• Abundant in blood, around 2x10^11 produced daily
• Short halflife: 8 hours

Found in circulation, main immune cells to eliminate bacterial pathogens

Question 8

What are some properties of eosinophils?

Answer 8

• Small numbers in blood, majority found in tissues
• Associated with fighting parasitic infections
  (Mice lacking eosionphils are still healthy however. Redundancy?)

Question 9

What are some properties of basophils?

Answer 9

• Similar to eosinophils - associated with fighting parasitic infections
• Recruitment to site of IgE-mediated allergic reactions
• Involved in helper T-cell differentiation
• Pathogenic role in allergic diseases

Question 10

What are some properties of mast cells?

Answer 10

• Associated with fighting parasitic infections; very potent providers of histamine
• Associated with pathogenic role in allergic diseases

Question 11

What are three key functions of mast cells?

Answer 11

• Recruiting other cells to site of infection
  Increase inflammation - increase lymph flow
• Muscular contractions for physical expulsion

Question 12

What are some properties of monocytes / macrophages?

Answer 12

• Tissue resident
• Relatively long-lived
• Phagocytic role
• Antigen presentation

Question 13

What are some properties of dendritic cells?

Answer 13

• Migratory and Resident; Mature and Immature

- Critical role in antigen capture and antigen presentation

Question 14

What is the difference between immature and mature dendritic cells?

Answer 14

Immature: Scanning in periphery. ‘Interested’ in phagocytosis
Mature: Activated for antigen presentation to T-cells

Question 15

What are some properties of Natural Killer cells?

Answer 15

• Activation by missing self

- Cytotoxicity and cytokine production

Question 16

How do naive lymphocytes through lymph nodes / spleen?

Answer 16

Blood

Question 17

Where do B cells hang out in the lymph nodes?

Answer 17

Cortex

Question 18

How do B cells get into the lymph nodes?

Answer 18

HEV (High endothelial venules)

Question 19

How do cells know where to go in the lymph node?

Answer 19

Secretion of chemokines / gradient

Question 20

Where are T cells found in the lymph nodes?

Answer 20

Paracortex

Question 21

How do migratory DCs get into the lymph nodes?

Answer 21

Via the lymph

Question 22

What is the role of the spleen?

Answer 22

• Damaged blood cells are cleaned out of circulation

- Filters blood borne antigens