Innate immunity review

Question 1

What Type of Receptor do Macrophages Use to Detect Pathogens?

Answer 1

• Pattern Recognition Receptors
• Recognize antigens (usually foreign proteins or polysaccharides) that are common to groups of pathogens e.g. cell wall material of Gram +ve bacteria

Question 2

What other types of receptors d phagocytic cells possess

Answer 2

Antibody receptors
Activated complement receptors

Question 3

Which cells are the professional phagocytes

Answer 3

Neutrophils and monocytes/macrophages/dendritic cells

Question 4

What are the sentinel cells

Answer 4

Macrophages/dendritic macrophages
Mast cells

Question 5

How are sentinel cells activated

Answer 5

Macrophage type
-PRR
Mast cells
-Have antibody, IgE, prebound on surface
-Antibody binds antigen
* Activates mast cell
* Pattern recognition receptors
* Receptors for activated complement

Question 6

How do we see when the innate immune system is activated

Answer 6

Inflammation

Question 7

Complement: what are the 3 pathways of activation

Answer 7

Classical: antibody dependent
Alternative: spontaneous activation of C3, but mammalian cells inactivate it
Lectin: PRRs for sugars in bacterial cell walls

Question 8

What protein is the first common step in all these pathways

Answer 8

C3

Question 9

Consequences of complement activation

Answer 9

Opsonisation
* Improved phagocytosis, makes antigen stick to phagocytes
Direct destruction of pathogens
* Membrane attack complex
Promotes inflammation
* Attract phagocytes
* Stimulate mast cells to degranulate

Question 10

How does the neutophil bind

Answer 10

PRR
Activated complement

Question 12

How does the innate immune system remove viruses in animals with no adaptive immunity?

Answer 12

• NK lymphocytes
• Interferon production