Infection 4 - Innate Immune System Flashcards Preview

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Flashcards in Infection 4 - Innate Immune System Deck (33):
1

Name some PHYSICAL barriers against infectious disease:

- Skin
- Mucous membranes (resp/GI/urinary tracts, mouth)
- Bronchial cilia

2

Name some PHYSIOLOGICAL barriers barriers against infectious disease:

- Diarrhoea
- Vomiting
- Coughing
- Sneezing

3

Name some CHEMICAL barriers against infectious disease:

- Stomach acid between pH 1-3
- Stomach pepsin
- Skin pH = 5.5
- Vaginal pH = 4.4
- IgA in tears/saliva/mucous membranes
- Lysozymes in sebum/perspiration/urine
- Mucous
- Beta-defensins on skin and mucous membranes

4

What is the pH of our skin?

pH = 5.5

5

What is the pH in the vagina?

pH = 4.4

6

Where in our bodies do we have normal flora?

- Nasopharynx
- Mouth
- Throat
- Skin
- GI tract
- Vagina

7

How does our normal flora protect us against infectious disease?

- They compete with pathogens for attachments sites and resources
- They produce antimicrobial chemicals

8

Name some bacteria which are commonly part of our normal flora on our skin:

- Staph. aureus
- Staph. epidermis
- Strep. pyogenes
- Cand. albicans
- Clost. perfringens

9

Name some bacteria which are commonly part of our normal flora in our nasopharynx:

- Strep. pneumoniae
- Neis. meningitidis
- Haemophilus spp.

10

Why are diabetics at high risk of infection?

Neuropathy:
- trauma goes unnoticed
- urine retention

High blood glucose
- bacteria thrive in
- deregulates neutrophil synthesis
- decreases complement response and leukocyte adherence

May result in acidosis, which limits immune system

11

Why are asplenic/hyposplenic patients at high risk of infection of encapsulated bacteria?

Spleen is essential for clearing encapsulated bacteria, as produces antibodies against them (IgM, IgG).
Amorphous polysaccharide coat impairs clearance without antibodies.

12

What bacteria should asplenic/hyposplenic patients be vaccinated against?

- Strep. pneumoniae
- Haem. influenza B
- Neis. meningitidis

13

What are the main functions of Macrophages?

- Phagocytosis
- Antigen presentation to T cells
- Produce cytokines and chemokines

14

How does the body respond to the TNF/IL-2/IL-6 released by macrophages?

- Vasodilation
- Increased vascular permeability
- Adhesion molecules stimulated

- Bone marrow activated = neutrophil mobilisation

- Hypothalamus stimulated to increase temperature

Liver produces:
- CRP = release of opsonins
- MBL = activates complement

15

Which immune cell makes up 60% of WBCs in the blood?

Neutrophils

16

What is the main function of neutrophils?

Phagocytose pyogenic bacteria (ie Staph. aureus/pyogenes)

17

Which immune cell has a multi-lobed nucleus?

Neutrophils

18

What are the main functions of eosinophils?

- Phagocytosis of antigen-antibody complexes
- Defence against parasites
- Allergic reactions

19

What is the main function of NK cells?

Induce apoptosis in all abnormal host cells

20

Which immune cells can present antigens to T cells?

- Macrophages/Monocytes
- Dendritic cells
- Langerhans cells
- B cells

21

What does PAMPs stand for?

Pathogen Associated Molecular Patterns

22

What is a Toll-Like Receptor (TLR)?

Pathogen Recognition Receptor, which recognises PAMPs

23

Which TLR recognises the Lipopolysaccharide coat of a gram negative bacteria?

TLR 4

24

Which TLR recognises the lipoproteins and lipoproteins of a gram negative bacteria?

TLR 2

25

Which TLR recognises the peptidoglycan of a gram positive bacteria?

TLR 2

26

Which TLR recognises the lipoteichoic acids of a gram positive bacteria?

TLR 4

27

Which TLR recognises the mannose-rich glycans of all mycobacteria?

TLR 2

28

Which TLR recognises bacterial flagella?

TLR 5

29

How is the complement cascade activated?

1) Binding of MBL to microbe
or
2) Initiated by endotoxins

30

Which complement proteins are responsible for the first stage in the cascade; the recruitment of phagocytes?

C3a
C5a

31

Which complement proteins are responsible for opsonising pathogens?

C3b
C4b

32

Which complement proteins are responsible for forming the membrane attack complex, and killing pathogens?

C5-C9

33

What are the 2 killing mechanisms used in phagocytosis?

1) O2 dependent = respiratory burst
2) O2 independent = lysozyme/lactoferrin/enzymes