Innate immunity Flashcards

1
Q

What are PRRss (+ example)

A

Proteins capable of recognizing molecules frequently found in pathogens (Pathogen-Associated Molecular Patterns)
e.g. Toll-Like Receptors - binds PAMPs –> activation results in cytokine expression –> cytokines activate immune cells & increase antivirial immunity

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2
Q

What cells do haematopoietic stem cells give rise to?

A

Myeloid-lineage cells
Lymphoid-lineage cells

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3
Q

Immune response - What are the lines of defence?

A
  1. Physical barriers
    * Surface barriers - skin, mucosal membranes
    * Epithelial cells - mechanical, selectively permeable barrier
  2. Innate immunity
  3. Adaptive immunity
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4
Q

What are phagocytes (+ examples)

A

Any cell capable of ingesting a foreign particle
* granulocytes (mainly neutrophils)
* Macrophages
* Immature dendritic cells

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5
Q

Neutrophils - Function & Characteristics

A

Function - Phagocytosis & activation of bactericidal mechanisms
* Rapidly invade site of infection
* Ingest bacteria
* Produce antimicrobial products incl. ROI & RNI
* activated neutrophils produce neutrophil extracellular traps (NETs)

Characteristics -
* are granulocytes - contain lysosomal granules
* constitute 30-70% of leukocytes in peripheral blood
* lots produced daily, but short-lived

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6
Q

Macrophage - Function & Characteristics

A

Function -
* Phagocytosis & activation of bactericidal mechanisms
* Antigen presentation

Characteristics -
* highly phagocytic & contain hydrolytic enzymes
* constitute 3-7% of leukocytes in peripheral blood
* Released as monocytes –> emigrate to tissues –> mature into macrophages

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7
Q

Dendritic cells - Function

A

Function -
* antigen uptake in peripheral sites
* Antigen presentation
* Bridge between innate & adaptive immune system

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8
Q

Types of granulocytes

A

Neutrophils
Basophils
Eosinophils

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9
Q

What is opsonisation?

A

‘Tagging’ pathogens for phagocytosis
* Opsonins (e.g. complement proteins, antibodies) form a surface film on the microbe which facilitates microbe recognition & binding by phagocytes

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10
Q

Basophils - Function + Characteristics

A

Function -
* promotion of allergic responses & augmentation of anti-parasitic immunity

Characteristics -
* contain large granules containing histamine, heparin, proteolytic enzymes
* least common granulocyte –> 0.1-0.3% of leukocytes in peripheral blood
* Last 1-2 days

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11
Q

Diseases/Conditions associated with high vs low basophil levels

A

High basophil levels:
* Allergic reactions - basophils release histamine (causes typical allergy symptoms)
* Chickenpox

Low basophil levels:
* cancer -
* Acute infection

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12
Q

Eosinophils - Function + Characteristics

A

Function - killing antibody-coated parasites

Characteristics -
* constitute 1-5% of leukocytes in peripheral blood
* important role in parasite infections, allergy & asthma

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13
Q

What is eosinophilia (+ causes & e.g.)

A

Eosinophilia - high eosinophil count
* occurs when either eosinophils are recruited to a specific site, or when the bone marrow produces too many

Caused by: many more
- parasitic & fungal diseases
- alleegic reactions
- skin disorders

Examples:
- asthma
- ezcema

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14
Q

Do antimicrobial peptides (AMPs) preferentially interact with host or bacterial membranes? why?

A

Bacterial membranes - because of strong (high-affinity) electrostatic interactions between (+)-charged AMP and (-)-charged phospholipids.

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15
Q

When do pathways on the complement cascade converge?

A

formation of C3 convertase

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16
Q

What are the 2 families of antimicrobial peptides

A
  1. Cethelicidins
  2. Defensins
17
Q

What are the 3 effector pathways of the complement cascade?

A
  • Inflammation
  • Lysis - via MAC
  • Opsonisation - enhances phagocytosis
18
Q

What cytotoxic granules do NK cells contain

A

Perforin - pore-forming protein
Granzymes - enter through perforin pore & destroy aberrant cells