Physiology: Innate Immune Response

Question 1

What is the epitope?

Answer 1

The part of the antigen that is recognised by the immune system

Question 2

Which cells are involved in the innate immune response?

Answer 2

Phagocytes
Eosinophils
Basophils
Mast cells
Natural Killer cells

Question 3

List the actions of the complement system in the innate immune response

Answer 3

Chemotaxis
Opsonisation
Cell lysis (e.g. of micro-organisms)
Solubilisation of immune complexes
Agglutination

Question 4

List the soluble mediators involved in the innate immune response

Answer 4

Acute phase reactants
Cytokines
Chemokines
Matrix metalloproteinases
Defensins

Question 5

Describe the role of toll-like receptors (TLR)

Answer 5

Innate immune response
Pattern-recognition receptors: bind to pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs)

Question 6

What is chemotaxis?

Answer 6

attraction and movement of macrophages towards a chemical stimulus

Question 7

What is opsonisation?

Answer 7

the process where foreign particles are marked for phagocytosis

Question 8

What is agglutination?

Answer 8

the process where antibodies cluster and bind pathogens together to make it easier for immune cells to attack

Question 9

Which mediators are opsonins? How do they work?

Answer 9

Opsonins: complement, antibodies, plasma proteins

Reduce repellent negative charge of cell membrane to allow phagocyte to come closer

Question 10

What are the main three pathways of the complement cascade?

Answer 10

Classical pathway
 - via antibodies bound to microbe/antigen
Alternative pathway
 - direct activation by microbe
Lectin pathway

Question 11

Describe the process of phagocytosis

Answer 11

1. Phagocyte moves towards microbe
2. phagocyte attaches to microbe via opsonin
3. endocytosis of microbe within phagosome
4. phagosome fuses with lysosome
5. oxygen-dependent species result in microbe death
6. release of microbe products

Question 12

Which cells act as phagocytes?

Answer 12

Neutrophils
Monocytes
Macrophages
Dendritic cells

Question 13

Which cells can become antigen-presenting cells?

Answer 13

Monocytes
Macrophages
Dendritic cells

Question 14

Which cells are generally the first to arrive at the site of an infection?

Answer 14

Neutrophils

Question 15

Which cells can attack multi-cellular parasites?

Answer 15

Eosinophils and Basophils

Question 16

Describe the role of dendritic cells

Answer 16

Antigen-presenting cells located in tissues exposed to external environment
Once activated, migrate to lymphoid tissues
- E.g. by binding to microbes via pattern recognition receptors
Also act as a bridge between innate and adaptive immune systems