Lecture 12 Extracellular bacteria

Question 1

What are the 3 general resistance factors for extracellular bacteria

Answer 1

Genetics
Hormonal status
Nutritional status

Question 2

What are the 7 ways innate antibacterial immunity protects against extracellular bacteria

Answer 2

TLR - mediated inflammation
Release of antibacterial proteins (defensins)
iron binding proteins
Lysozyme
Activation of alternate and lectin pathways
NK cells
Inteferons

Question 3

What are the four basic mechanisms to fight extracellular bacteria for acquired immunity

Answer 3

Neutralisation of toxins/enzymes by antibodies
Killing of bacteria by antibodies, complement and lysozome
Opsonisation
Phagocytosis and intracellular destruction

Question 4

Describe the two types of toxin producing bacteria

Answer 4

Type I toxin producing bacteria the toxin is produced is the only virulence factor of the microbe
Type II toxin producing bacteria - the toxin produced is a major virulence factor but there are others

Question 5

Describe toxin neutralisation in accordance to protection against toxin producing bacteria

Answer 5

1. Toxin neutralisation
   - Abs bind to toxins and destroy them as they cannot
   bind to their receptors and the toxin Ab complex will
   be phagocysed

Question 6

Describe opsonisation in accordance to protection against toxin producing bacteria

Answer 6

Opsonisation
- Collectins bind to bacteria and opsonise them, the C
terminal on collectins recognise bacteria
carbohydrate ligands.

Question 7

Describe the response to lipopolysaccharides in response to protection agaisnt toxin producing bacteria

Answer 7

Response to lipopolysaccharides (LPS)
- LPS main component that induces inflammation, binds with LPS binding protein and CD14. This attachment stimulates cytokines and prostaglandins. This generates acute inflammation in tissues and circulation and results in septic shock

Question 8

What toxins do C.tetani produce and what tissues do they act on

Answer 8

Tetanus toxin binds to nerve cells in nervous tissue produces spasms

Question 9

What toxins do C.botulinum produce and what tissues do they act on

Answer 9

Botulinum toxins interfere with release of acetyl choline (neurotransmitter)

Question 10

What toxins do C.perfringens produce and what tissues do they act on

Answer 10

alpha toxin attacks cell membrane and kills cells

beta toxin causes ulcers

Question 11

What toxins do B.anthracis produce and what tissues do they act on

Answer 11

Complex exotoxin consisting of protective antigen, oedma factor and lethal factor. Disease is peracute - septicaemia and death

Question 12

What toxins do V.cholerae produce and what tissues do they act on

Answer 12

Enterotoxin binds to epithelial cells and secretes fluids - results in diarrhoea

Question 13

What toxins do enterobacteriaceae produce and what tissues do they act on

Answer 13

Present in gut, produce endotoxins, released after bacterial cell lysis. Lipopolysaccharide protein complex toxins, Lipid A active component of toxin