Lecture 4: White blood cells

Question 1

Describe mast cells

Answer 1

In tissues only

Release substances that affect vascular permeability

Prominent in mucosal and epithelial tissues

Express FCeRI (binds IgE)

Question 2

What are the %s of each leukocyte?

Answer 2

Neutrophils - 50-70%
Lymphocytes - 20-40%
Monocyte - 3-10%
Eosinophil - 1-3%
Basophil - <1%

Question 3

Describe basophils

Answer 3

Lobed nuclei and heavily granulate cytoplasm

Non-phagocytic cells

Function by releasing pharmacologically active substances from their cytoplasmic granules

They circulate in the blood

Recruited to sites of allergic reactions or parasite infection

Express FCeRI - can bind IgE and degranulate

Question 4

Eosinophils

Answer 4

Have bilobed nuclei and granulated cytoplasm

Motile phagocytic cells that migrate from blood into the tissues

recruited to sites of allergic reactions

Express FCeRI upon activation

Granules containing toxins e.g. peroxides

Question 5

Neutrophils

Answer 5

Multilobed nucleus

Found in the blood

Rapidly recruited to sites of infection/injury

Short lifespan (8 hr- 4 days)

Myeloperoxidase and ROS

Question 6

Monocytes

Answer 6

Kidney-shaped nucleus

Reservoir of monocytes in the spleen

Also circulate in bloodstream where they enlarge

Migrate into tissues approx. 1 day after release from the bone marrow

Question 7

Macrophages

Answer 7

Found in tissues (they are tissue specific)

5-10-fold larger than monocytes

Contain many more organelles compared to monocytes e.g. lysosomes

Lifespan is months to years

Question 8

What type of cell increases in response to a bacterial infection?

Answer 8

Neutrophils (and monocytes in chronic infection)

Question 9

What type of cell increases in response to a viral infection?

Answer 9

Lymphocytes and sometimes monocytes

Question 10

What type of cell increases in response to a parasitic infection?

Answer 10

Eosinophils and mast cells

Question 11

What type of cell increases in response to a fungal infection?

Answer 11

Monocytes

Question 12

What type of cell increases in response to an allergic infection?

Answer 12

Basophils (and eosinophils in chronic phase) and mast cells

Question 13

Overview of the inflammatory response

Answer 13

Blood vessels dilate

Blood vessels become more permeable

Circulating leukocytes migrate into tissues

Leukocytes are activated

Activated leukocytes destroy microbes and unwanted material

Question 14

What cell is present in acute infection?

Answer 14

Neutrophils

Resolves once stimulus is removed

Question 15

What cells are present in chronic infection?

Answer 15

Macrophages and lymphocytes

Tissue destruction and attempts at healing

Question 16

What are cytokines?

Answer 16

<30kDa

Regulatory proteins or glycoproteins

Act as messenger molecule of the immune system

Secreted primarily by white blood cells

Act locally (paracrine)

Question 17

What are chemokine?

Answer 17

Type of cytokine that induce directed chemotaxis in local responsive cells

Functions as attractants for leukocytes, recruiting monocytes and neutrophils to site of infection

MCP-1

Question 18

What molecules are involved in initial contact between leukocytes and the endothelium?

Answer 18

P and E selections on the endothelium recognised by oligosaccharides on leukocytes (sulphated silly-Lewis^x)

Question 19

What molecules are involved in tight adhesion between leukocytes and the endothelium?

Answer 19

Intercellular adhesion molecules (ICAMs) on endothelium recognised by integrins on leukocytes

Question 20

Name three pro inflammatory cytokines from activated macrophages

Answer 20

IL-1b, TNFa, IL-6

Question 21

What is the ligand for macrophage mannose receptors?

Answer 21

Conserved carbohydrate structures

Question 22

What is the ligand for scavenger receptors?

Answer 22

Anionic polymers, acetylated and oxidised LDL

Question 23

What is the ligand for TLRs?

Answer 23

There are loads