PATH Immune lecture 1

Question 1

Describe three constitutive barriers to infection

Answer 1

Skin
Mucosal surfaces
Commensal bacteria

Question 2

Explain how the skin prevents infection

Answer 2

Skin:
tightly packed keratinised cells prevents colonisation by microorganisms
Low pH, low oxygen tension
Sebaceous glands:
Hydrophobic oils repel
microorganisms
Lysozyme destroys bacterial cell wall
Ammonia and defensins have antimicrobial properties

Question 3

Explain how mucosal surfaces prevent infection

Answer 3

Mucous traps pathogens
IgA prevents bacteria/viruses attaching to epithelial cells
Lysozyme kills invading pathogens
Lactoferrin starves invading bacteria of iron

Question 4

Explain how commensal bacteria prevent infection

Answer 4

Compete with pathogenic microorganisms for scarce resources
Produce fatty acids that inhibit the growth of pathogens

Question 5

Describe the components of the innate immune system

Question 6

Where are polymorphonuclear cells produced

Answer 6

Bone marrow, then migrate rapidly to the site of infection

Question 7

List some polymorphonuclear cells

Answer 7

Neutrophils, eosinophils, basophils

Question 8

What receptors do PMN cells contain and why?

Answer 8

Fc receptor to bind to Ig

Question 9

What do monocytes and macrophages do?

Answer 9

Circulate in the blood and migrate to where needed, where they differentiate into macrophages

Present antigen to T cells

Question 10

What do you call a macrophage in the liver?

Answer 10

Kupffer cell

Question 11

What do you call a macrophage in the spleen?

Answer 11

Sinusoidal lining cell

Question 12

What do you call a macrophage in the kidney?

Answer 12

Mesangial cell

Question 13

What do you call a macrophage in the bone?

Answer 13

Osteoclast

Question 14

What do you call a macrophage in the lung?

Answer 14

Alveolar macrophage

Question 15

What do you call a macrophage in the neurons?

Answer 15

Microglia

Question 16

What do you call a macrophage in the skin?

Answer 16

Langerhans cells

Question 17

What do you call a macrophage in the connective tissue?

Answer 17

Histiocyte

Question 18

Explain how phagocytes are recruited to a site

Answer 18

Cell damage and bacterial products trigger local production of inflammatory chemokines and cytokines; causing vascular endothelial permeability. CHEMOKINES attract phagocytes

Question 19

How does the body pick up a pathogen?

Answer 19

PAMPS - pathogen associated molecular patterns - are picked up by TLRs and mannose receptors

Question 20

PahWhat helps with endocytosis of pathogens? List three types

Answer 20

Opsonisation:
Ab bound to Fc receptors
Complement binding to complement receptors like CR1
Acute phase proteins (CRP)