Responses to bacterial infection

Question 1

Examples of extracellular pathogens?

Answer 1

1. Streptococci pyogenes
2. Schistosoma mansoni
3. Staphylococcus Aureus
4. Haemophilus Influenza

Question 2

Examples of intracellular pathogens?

Answer 2

1. Mycobacterium tuberculosis
2. Listeria monocytogenes
3. Viruses

Question 3

What are the mechanisms of innate immunity to extracellular microbes?

Answer 3

1. Complement activation
2. Phagocytosis
3. Inflammation

Question 4

Mechanisms of adaptive immunity to extracellular microbes?

Answer 4

1. T helper cells

2. Antibodies

Question 5

Medical conditions caused by Streptococci?

Answer 5

• pharyngitis
• Impetigo
• Scarlet fever
• Cellulitis
• TSS
• Pneumonia
• Necrotizing fascitis

Question 6

What are TLR’s?

Answer 6

• Membrane spanning receptors
• Diff types discriminate between different pathogens and drive different responses
  e. g, cause different interlukens to be released. Different IL’s have diff functions

Question 7

What does IL- 1, TNF, and IL-6 do?

Answer 7

-Induces inflammation

Question 8

What does IL-12, IL-10, and IL-23 do?

Answer 8

• Cause T cell differentiation

- Streptococci cause IL-23 to be made.

Question 9

What does Th1 do?

Answer 9

• Involved in intracell. bacterial infections and autoimmunity
• Driven by IL-1, TNF, IL-12

Question 10

What does Th2 do?

Answer 10

• Involved in helminth infections and asthma and allergy.
• Produce IL-4 and IL-5. This causes the prod. of IgE from B cells, in turn activating mast cells.
• Driven by IL-10

Question 11

What does Th17 do?

Answer 11

• involved in extracelular bacterial or yeast infections and autoimmunity
• Driven by IL-1, TNFm IL-6, and IL-23

Question 12

Two methods of B cell activation?

Answer 12

1. T dependent
   - Produces long-lived plasma cells and B memory cells.
   - Produces IgA, IgG and IgM.
   - In response to a protein antigen.
2. T independent
   - Produces short-lived plasma cells and no memory cells
   - In response to a polysaccharide antigen (e.g from the outer coat of streptococci).
   - Produces IgM only.

Question 13

What are the main responses against extracellular bacteria?

Answer 13

Inflammation
Comp activation
Th17 cells
Antibodies

Question 14

What are the main responses against helminths?

Answer 14

Th2 cells

Eosinophils and mast cells

Question 15

What are the main responses against viruses?

Answer 15

Antibodies (neutralisation only)
IFN release
CyT cells
NK cells

Question 16

What are the main responses against intracellular bacteria?

Answer 16

Th1 cells

IFN gamma