Intro to immunology Flashcards

1
Q

What are the major physical barriers to infection?

A

Saliva
Mucocilliary Escalator
Gastric Acid
Natural Flora
Flushing & urine pH

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2
Q

What cell types are involved in innate immunity?

A

In blood:
- NK cells
- Basophils
- Eosinophils
- Monocytes

In Tissue
- Mast Cells
- Macrophages
- Dendritic Cells

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3
Q

By what mechanisms does the innate immune system function?

A

1) Inflammation
2) Recruiting immune cells
3) Complement Activation
4) Opsonisation
5) Phagocytosis
6) NK cytotoxicity

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4
Q

What are cytokines?

A

Molecules that regulate the nature, duration & intensity of immune responses by binding to specific receptors
E.g. Interleukins, TNF-alpha, chemokines & TGF-beta

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5
Q

Where are cytokines made?

A

Th cells & Macrophages

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6
Q

Which cytokines are pro and anti-inflammatory?

A

Pro-inflammatory = TNF-alpha, IL-1, IL-6 & chemokines

Anti-inflammatory = IL-10 & TGF-beta

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7
Q

Describe what happens during inflammation?

A

Pattern Recognition Receptors (PRR) detect a breach in defence/foreign body and trigger:
- Vasodilation
- Vascular permeability
- Cell Adhesion Molecules
- Chemotaxis
- Sensitivity to Pain

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8
Q

How is complement activated?

A

C3 is activated first. By any of the 3 pathways, Classical/Lectin/Alternative

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9
Q

What are the functions of complement?

A

Chemotaxis of phagocytes
Opsonisation
Lysis of micro-organisms
Maintain solubility of Ab/Ag complexes

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10
Q

What is Opsonisation?

A

Tagging cells for phagocytosis
Done by complement C3b/C4b, antibodies & plasma cells

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11
Q

What do NK cells do in innate immunity?

A

Perforin-induced Apoptosis

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12
Q

Define an antigen vs antibody?

A

Antigen is any molecule that induces an immune response. An antibody is a glycoprotein made by b cells that binds antigens

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13
Q

What are the 2 types of adaptive immunity?

A

Humoral - B cells & Abs
Cell-mediated - T Lymphocytes

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14
Q

How do adaptive immune cells recognise antigens?

A

B cells/Abs detect BCR directly

T cells detect MHC on antigen presenting cells

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15
Q

Immune Tolerance is a process of ensuring our Lymphocytes are tolerant towards our own tissues. Where does this occur?

A

Central Tolerance:
T = Thymus
B = Marrow

Peripheral Tolerance:
- 2nd lymphoid organs & circ

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16
Q

What happens during central tolerance?

A

B cells assessed for self-reacting BCR in the marrow.

T cells undergo +ve (can they recognise foreign antigen?) & -ve (Do they not recognise self-antigens) tolerance testing in the thymus.
Any failures die

17
Q

How does peripheral tolerance work?

A

Regulatory T cells destroy self-reactive lymphocytes

18
Q

What are the major types of T cells?

A

Cytotoxic (CD8+)
Helper (CD4+)
Regulatory

19
Q

What do CD8+ T cells do?

A

Cytotoxic
They induce apoptosis in target cells and release anti-viral/tumour cytokines (IFN-gamma & TNF-alpha)

20
Q

What do CD4+ T cells do?

A

Helper:
Activate B cells

Also release cytokines and activate other inflammatory cells e.g. macrophages, mast cells, basophils etc.

21
Q

Which type of Th cell attacks which type of pathogen?

A

Th1 targets intracellular pathogens

Th2 & Th17 target extracellular pathogens

22
Q

Other than peripheral tolerance, what else do regulatory T cells do?

A

Secrete anti-inflammatory Cytokines (IL-10 & TGF-beta)

Suppress Th & cytotoxic T cells

23
Q

Which immunoglobulins are monomers, dimers & pentamers?

A

Monomer - IgG, IgE, IgD

Dimer = IgA

Pentamer = IgM

24
Q

Which immunoglobulin can cross placenta?

A

IgG

25
Q

Which immunoglobulin is involved in parasites and allergies?

A

IgE

26
Q

Which antibody activates complement?

A

IgM

27
Q

What are the functions of immunoglobulins?

A

1) Immune complex formation
2) Opsonisation
3) Classical Complement Activation
4) Ab-dependant Cellular Cytotoxicity (ADCC)

28
Q

What are the major causes of Secondary Immune Deficiency?

A

Environmental e.g. malnutrition or trauma

Disease e.g. HIV, DM, malignancy or renal failure

Drugs e.g. Glucocorticoids, cyclosporin or Rituximab