Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Infection > The Innate Immune Response > Flashcards

The Innate Immune Response Flashcards

1
Q

What is the immune system?

A

Cells and organs that contribute to immune defences against infectious and non-infectious conditions

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

What is an infectious disease?

A

When the pathogen succeeds in evading and/or overwhelming the host’s immune defences

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

What are the roles of the immune system?

A
  • Pathogen recognition (by cell surface and soluble receptors)
  • Containing/eliminating the infection (killing and clearance mechanisms)
  • Regulating itself (minimum damage to the host)
  • Remembering pathogens (to prevent recurrent disease)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is innate immunity?

A
  • Immediate protection
  • Fast (within seconds)
  • Lack of specificity
  • Lack of memory
  • No change in intensity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is adaptive immunity?

A
  • Longer lasting protection
  • Slow (days)
  • Highly specific
  • Immunologic memory
  • Changes in intensity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What factors prevent entry and limit the growth of a pathogen?

A

First lines of defence

  • Physical barriers
  • Physiological barriers
  • Chemical barriers
  • Biological barriers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are physical barriers?

A
  • Skin
  • Mucosal membranes (mouth/respiratory tract/GI tract/Urinary tract)
  • Bronchial cilia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What physiological barriers exist in the innate immune response?

A
  • Diarrhoea (in food poisoning)
  • Vomiting (food poisoning/hepatitis/meningitis)
  • Coughing (pneumonia)
  • Sneezing (sinusitis)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What chemical barriers are found in the innate immune response?

A
  • Low pH
  • -> skin = 5.5, stomach = 1-3, vagina = 4.4
  • Antimicrobial molecules
  • – IgA (tears, saliva, mucous membranes)
  • – Lysozyme (sebum, perspiration, urine)
  • – Mucus (mucous membranes)
  • – Beta-defensins (epithelium)
  • – Gastric acid + pepsin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What biological barriers exist in the innate immune response?

A

Normal flora exists of non-pathogenis microbes in strategic locations

  • Nasopharynx
  • Mouth/throat
  • Skin
  • GI tract
  • Vagina
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the benefits of a normal flora?

A
  • Compete with pathogens for attachment sites and resources
  • Produce antimicrobial chemicals
  • Synthesise vitamins (K, B12, other B vitamins)
  • Immune maturation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What normal flora are found in the skin?

A
  • Staphylococcus aureus
  • Staphylococcus epidermidis
  • Streptococcus pyogenes
  • Candida albicans
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What normal flora are found in the mouth and nasopharynx?

A
  • Streptococcus mutans
  • Streptococcus pneumoniae
  • Neisseria meningitidis
  • Haemophilus species
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What normal flora are found in the GI tract?

A

E. Coli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What has to happen to the flora to cause clinical problems?

A

Normal flora has to be displaced from its normal location to sterile locations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What breaches the skin integrity?

A
  • Skin loss (burns)
  • Surgery
  • IV lines
  • Skin diseases
  • Injection drug users
  • Tattooing/body piercing
17
Q

What other things cause displacement of the normal flora to sterile environments?

A
  • Fecal-oral route (foodborne infection)
  • Fecal-perineal-urethral route (UTI, mostly in women)
  • Poor dental hygiene/dental work (dental extraction/ gingivitis/ brushing flossing)
  • Normal flora overgrows and becomes pathogenic when host is immuno-comprimised
  • Normal flora in mucosal surfaces is depleted by antibiotic therapy
18
Q

What patients are high risk of serious infections relating to the displacement of normal flora?

A
  • Asplenic (and hyposplenic) patients
  • Patients with damaged or prosthetic valves
  • Patients with previous infective endocarditis
19
Q

What makes up the second line of defence in the innate immune response?

A
  • Phagocytes
  • Compliment system
  • Cytokines
20
Q

What are the main phagocytes and other key cells in innate immunity

A
  • Macrophages
  • Monocytes
  • Neutrophils (pus)
  • Basophils/ mast cells
  • Eosinophils
  • Natural Killer Cells
  • Dendritic Cells
21
Q

What is the function of the macrophage?

A
  • Present in all organs
  • Ingest and destroy microbes (phagocytosis)
  • Present microbial antigens to T cells (adaptive immunity)
  • Produce cytokines/chemokines
22
Q

What is the function of the monocyte?

A
  • Present in the blood

- Recruited at infection site and differentiate into macrophages

23
Q

What is the function of neutrophils?

A
  • Present in the blood
  • Increased during infection
  • Recruited by chemokines to site of infection
  • Ingest and destroy pyogenic bacteria: Staph. aureus and Strep. pyogenes
24
Q

What is the function of basophils/mast cells?

A
  • Early actors of inflammation (vasomodulation)

- Important in allergic reactions

25
Q

What is the function of eosinophils?

A

Defence against multi-cellular parasites (worms)

26
Q

What is the function of natural killer cells?

A
  • Kill all abnormal host cells (virus infected or malignant)
27
Q

What is the function of dendritic cells?

A
  • Present microbial antigens to T cells (acquired immunity)
28
Q

What is involved in phagocytes specific pathogen recognition?

A

Microbial structures: Pathogen-associated molecular patterns (PAMPs)
- Carbohydrates, lipids, proteins, nucleic acids

Phagocytes: Pathogen Recognition Receptors (PRRs)
- Toll like receptors

Opsonisation of microbes
- Coating microbes in opsonins to lead to enhanced attachment and clearance of microbes

29
Q

What PAMPs interact PRRs in innate cell?

A

Gram negative bacteria and cognate PRRs

  • Lipopolysaccharide (LPS) –> TLR4
  • Lipoproteins and lipopeptides –> TLR2

Gram positive bacteria

  • Peptidoglycan –> TLR2
  • Lipoteichoic acids –> TLR4

All mycobacteria
- Lipoarabinomannan and Mannose-rich glycans –> TLR2

Bacterial flagella
-Flagellin –> TLR5

30
Q

Examples of opsonins?

A

Complement proteins

  • C3b
  • C4b

Antibodies (best opsonins)

  • IgM
  • IgG

Acute phase proteins

  • C-reactive protein
  • Mannose-binding lectin (MBL)
31
Q

Which encapsulated bacteria are cleared with opsonins?

A
  • Neisseria meningitidis
  • Streptococcus pneumoniae
  • Haemophilus influenzae b
32
Q

What are phagocyte intracellular killing mechanisms?

A

Oxygen-dependent pathway (respiratory burst)
- Toxic O2 products for the pathogens: hydrogen peroxide, hydroxyl radical, nitric oxide, singlet oxygen, hypohalite

Oxygen-independent pathways

  • Lysozyme
  • Lactoferrin or transferrin
  • Cationic proteins (cathepsin)
  • Proteolytic and hydrolytic enzymes
33
Q

What is the complement system?

A
  • Composed of multiple serum proteins
  • Interaction with the microbes via different pathways
  • Production of biologically active components called C1-C9
34
Q

What are the different pathways of the complement system?

A
  • Classical pathway initiated by antibody-antigen interaction
  • Alternative pathway initiated by cell surface microbial constituents (endotoxin on E. Coli)
  • MBL pathway initiated when MBL binds to mannose containing residues of proteins found on many microbes
35
Q

What are the microbial actions of complement proteins?

A

Divided into two groups, a= attraction b= binding

C3a and C5a = recruitment of phagocytes
C3b = Opsonisation of pathogens
C5-C9 = Killing of pathogens via membrane attack complex

36
Q

What happens when phagocytosis is reduced?

A

Decreased spleen function

  • Asplenic patients
  • Hyposplenic patients

Decreased neutrophil number

  • Cancer chemotherapy
  • Certain drugs (phenytoin)
  • Leukaemia and lymphoma

Decreased neutrophil function

  • Chronic granulomatous disease (no respiratory burst)
  • Chediak-Higashi syndrome (no phagolysosome formation)

Infection (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions