Antibacterial responses Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

What are the key steps in infection?

A

entry,

invasion and colonisation of host tissue

evasion of immunity

tissue damage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the features of immunity to bacteria?

A

Defence mechanisms against microbes comprise both innate and adaptative system

Specialised to different types of bacteria

Pathogenicity and survival of the bacteria is influenced by the ability to evade the effector mechanism of immunity

Some bacteria establish latent or persistent infection and the immune system does not clear the microbe

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the first line of defence in an infection?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are anti-microbial peptides?

A

Are capable of killing by penetrating microbial membranes thus disrupting their integrity

They are active against bacteria, fungi and enveloped and non-enveloped viruses

2 types:

Alpha-defensins

  • Secreted mainly by neutrophils and Paneth cells

Beta-defensins

  • Secreted by a broad range of epithelial cells, in particular, those in the respiratory tract, the skin and the urogenital tract
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Whats the 1st step if the intial barriers are broken through in a infection?

A

Complement

Has the ability to detect PAMPs due to containing certain molecules - so can be described as a PRR - ‘classical pathway’

Can recognise gram-positive or gram-negative bacteria carbohydrates and activate alternative pathway of complement

Bacteria that has mannose on the surface of the bacteria can active the lectin pathway of complement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the different complement functions?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the consequences of detection of PAMPs by PRRs?

A

Phagocytosis and cytokine production

–> this then leads to inflammation (due to chemokines and cytokines)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How does inflammation occur?

A

Initiates by detection of infection normally a resident cell in the tissue which will get activated

This will then start producing inflammatory cytokines (IL-1, IL-6 and TNF-a)

Chemokines will have a reaction in the endothelium and beyond - allowing for circulating leukocytes to go into the site of damage or infection (first neutrophils, then monocytes, then lymphocytes)

Mast cells release histamine and prostaglandins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are neutrophils?

A

Perform phagocytosis and they degranulate granules –> intracellular killing of bacteria

Phagocytosis and oxidative burst kills the bacteria

They have a special system of NETs (neutrophils extracellular traps) - suicide system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How do antibodies neutralise bacterial toxins?

A

Trigger classical complement pathway by binding of IgM to bacteria

  • As a consequence, bacterial cell surface is coated in C3b facilitating its phagocytosis

Opsonisation - coating of bacteria to aid phagocytosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the difference between Humoral and cellular response?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What do helper T cells do?

A

enhance phagocytosis of extracellular pathogens by activating macrophages

How well did you know this?
1
Not at all
2
3
4
5
Perfectly