Innate Immunity

Question 1

Difference between innate and adaptive immunity

Answer 1

Innate - immediate protection, fast, lack of specificity, lack of memory, no change in intensity
Adaptive - Long lasting protection, slow, specificity, immunological memory, increased intensity with repeated exposure.

Question 2

Define immune system

Answer 2

The cels and organs that contribute to immune defences against infectious and non-infectious diseases.

Question 3

What are the first lines of defence in innate immunity

Answer 3

Physical barriers
Physiological barriers
Biological barriers
Chemical barriers

Question 4

Give some physical barriers

Answer 4

Skin
Mucous membranes
Bronchial cilia

Question 5

Give some physiological barriers

Answer 5

Ejections of pathogen - cough/sneeze/diarrhoea, vomiting

Question 6

Give some chemical barriers

Answer 6

Low pH in stomach/skin/vagina

Antimicrobial molecules - IgA, Lysosyme, Gastric acid

Question 7

Give some biological barriers

Answer 7

Normal flora compete for space and recourses, produce antimicrobial molecules.

Question 8

When do normal flora cause rouble

Answer 8

Displaced from normal site
Overgrow in immunocompromise
Depleted by antibiotics

Question 9

What is the 2nd line of defence in innate immunity

Answer 9

Factors that contain and clear infection:
Phagocytes
Chemicals that lead to inflammation

Question 10

Give macrophage fucntions

Answer 10

Phagocytosis
Antigen presentation
Produce cytokines and chemokines

Question 11

Give non phagocytic innatee immune cels

Answer 11

Basophils/mast cells
Eoisinophils
NKC
Dendritic cells

Question 12

How are pathogens recognised

Answer 12

Pathogen Associated Membrane Patterns (PAMPS) on pathogens are recognised by Pathogen Recognition Receptors (PRRs)

Question 13

Describe opsonisation and give some opsonins

Answer 13

Coating proteins bind to microbial surface molecules leading to enhanced attachment of phagocytes
C3b/C4b
IgG/IgM
CRP

Question 14

Opsonins are essential in clearing…

Answer 14

Encapsulated bacteria:
NEisseria meningitius
Haemophilius influenza
Sterp pneumonia

Question 15

Give phagocyte killing mechanisms

Answer 15

O2 dpendent - ROS

O2 independent - enzymes

Question 16

Describe the complement pathway

Answer 16

20 serum proteins
Activated by cell surface microbial constiuents or by MBL
C3a/C5a - Inflammatory mediators/chemokines
C3b/C4b opsonins
C5-C9 membrane attack comples

Question 17

Give some cytokines and chemokines and their function

Answer 17

TNFa, IL1, IL6
CRP/MBL release
Neutrophil modilisation
Vasodilation
Increased vacs permeabiltiy

Question 18

why is the spleen important

Answer 18

spleen holds half the body’s monocytes

polysaccharide encapsulated bacteria resist opsonisation so spleen must clear by producing natural antibodies