Intro to immunology Flashcards

1
Q

Skin - how does it act as a barrier to infection?

A
  • Physical barrier - tightly packed keratinised cells
  • Low pH
  • Low oxygen tension
  • Sebaceous glands produce hydrophobic oils + lysozymes
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2
Q

Secreted mucous - 4 ways that it acts as a barrier to infection?

A
  • Secretory IgA
  • lysozyme
  • Lactoferrin (starves bacteria of iron)
  • Physical barrier
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3
Q

Commensal bacteria - how doe sit act as a barrier to infection?

A
  • Compete with pathogenic organisms for scarce resources

- Produce fatty acids and bactericides that inhibit pathogen growth

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4
Q

Polymorphonuclear cells inc?

A

Neutrophils
Eosinophils
Basophils/mast cells

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5
Q

Actions of polymorphonuclear cells

A
  • Migrate rapidly to site of injury
  • Secrete cytokines and chemokines
  • Express receptors for cytokines + pattern recognition + Fc of Ig
  • Phagocytosis + non/oxidative killing
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6
Q

How do macrophages differ from polymorphonuclear cells?

A

Present processed antigen to T-cels

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7
Q

Cytokines vs chemokine

A
Cytokines = increase vascular permeability
Chemokine = attract phagocytes
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8
Q

2 ways in which microorganisms are recognised by innate immune response?

A
  1. Pattern recognition receptors - eg TLRs and mannose receptors
  2. Fc receptors - for Fc portion of Ig to allow recognition of immune complexes
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9
Q

Which molecules facilitate endocytosis?give 3 egs

A

Opsonisation

  • Antibodies (bind to Fc receptors)
  • Complement components
  • Acute phase proteins (CRP)
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10
Q

2 killing methods by polymorphonuclear cells?

A

Oxidative killing - NADPH oxidase complex converts O2 to reactive oxygen species. Myeloperoxidases: production of hydrochlorous acid (an antimicrobial!)

Non-oxidative killing - release of lysozyme/lactoferrin from granules into phagolysosyme

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11
Q

What happens after neutrophils after they phagocytose lots?

A

Depletes neutrophil glycogen reserves –> neutrophils die –> residual enzymes released –> accumulate –> pus

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