Innate Immunity Flashcards

1
Q

3 Polymorphonuclear cells of the innate immune system

A

Neutrophils, Eosinophils, Basophils

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2
Q

What do dendritic cells do?

A

Link between innate and adaptive

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3
Q

2 types of dendritic cells:

A

Dendritic Cell and Follicular Dendritic Cell

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4
Q

Difference between dendritic cells and follicular dendritic cells: 5

A

Dendritic cells are widespread, have MHC II, CD 80 and 86, are phagocytic and show processed Ag to T cells
FDC: In germinal centers of secondary lymphoid, no MHCII, no CD80 and CD86, no phagocytosis, show naive antigen to b cells

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5
Q

What are dendritic cells in skin called?

A

Langerhan’s cells

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6
Q

What do CD80 and CD86 interact with? what happens if none?

A

CD28 on T cells - if absent, T cells programs death

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7
Q

What do eosinophils act against? how?

A

Large parasites - release granule contents for extracellular killing

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8
Q

What is in eosinophil granule content?4

A

Major basic proteins, cationic protein, oxygen metabolites, perforin

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9
Q

What is the main role of basophils and mast cells?

A

Getting rid of parasitic worms

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10
Q

How do basophils and mast cells work?

A

Coat themselves with IgE by FcE receptor. Antigen cross links 2 FcER — inflammatory mediators released

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11
Q

5 Inflammatory mediators from basophils and mast cells (Stored and new):

A

Stored: Histamine and serotonin
New: TNF alpha, prostaglandin, leukotrienes

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12
Q

5 molecules of innate immunity:

A

PRRs, complement, APP, Defensins, Cytokines

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13
Q

3 things acute phase response does:

A

1- Enhances host resistance to infections and minimises tissue injury
2- Promotes resolution and repair of inflammatory lesions
3- Cytokines release due to PRR activation, act on liver to increase secretion of APP

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14
Q

3 cytokines that act on the liver in APP

A

IL1 , IL6, TNF

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15
Q

3 things produced by liver during APP:

A

1- C3 complement component
2- C-reactive protein which activates complement
3- Fibrinogen coagulation

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16
Q

What are defensins? 4

A
  • Nature’s antibiotic
  • Small cationic antimicrobial peptides
  • Widely expressed, esp by leukocytes and epithelium
  • Intracellular and secreted
17
Q

Two types of defensins - difference:

A

alpha defensins - constitutively expressed

beta defensins - some constitutively expressed, others induced

18
Q

How does immune system recognise antigens?

A

Use intracellular, cell surface and secreted PRRs

19
Q

What does the PRR recognise?

A

PAMPS and DAMPs

20
Q

Protein diversity of PRRs in individual:

A

10s - 100s

21
Q

Genes of PRR:

A

Each protein individually encoded, low polymorphism

22
Q

What are TLRs?

A

A large group of PRRs.

23
Q

3 TLRs on cell surface + what recognise:

A

TLR2- lipoproteins (gram +ve proteoglycan)
TLR4 - LPS (gram -ve)
TLR5- flagellum

24
Q

4 TLRs endosomal compartment + recog:

A

TLR3 - viral dsRNA
TLR 7 and 8 - ssRNA nucleotide analogue
TLR9 - unmethylated CPG DNA

25
What do TLRs do?
Activate NFkB and IRF
26
What does mannose receptor detect?
Terminal mannose
27
What is the complement system?
Large number of molecules, many are pro - go on and activate another enzyme in a cascade like fashion
28
Opsonisation
Coating a microorganism to make it more readily recognisable by the phagocytic cell
29
What are the two main types of molecules that opsonise microorganisms?
Antibodies and complement proteins
30
How does opsonisation work?
Phagocytic cells have molecules on their cell surface that recognises the ab or complement (CR)
31
What are complement components also involved in?
chemotaxis and increasing vascular permeability as they make mast cells and basophils release inflammatory mediators
32
What are cytokines?
Small secreted proteins that act as messengers between cells
33
5 main groups of cytokines are:
IL, Colony stim factors, chemokines, IFN, TNF
34
Functions of cytokines include 2:
control of Haematopoiesis and immune responses