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Flashcards in Intro to immunology Deck (28)
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1

What are the major physical barriers to infection?

Saliva
Mucocilliary Escalator
Gastric Acid
Natural Flora
Flushing & urine pH

2

What cell types are involved in innate immunity?

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

In Tissue
- Mast Cells
- Macrophages
- Dendritic Cells

3

By what mechanisms does the innate immune system function?

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

4

What are cytokines?

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

5

Where are cytokines made?

Th cells & Macrophages

6

Which cytokines are pro and anti-inflammatory?

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

Anti-inflammatory = IL-10 & TGF-beta

7

Describe what happens during inflammation?

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

8

How is complement activated?

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

9

What are the functions of complement?

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

10

What is Opsonisation?

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

11

What do NK cells do in innate immunity?

Perforin-induced Apoptosis

12

Define an antigen vs antibody?

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

13

What are the 2 types of adaptive immunity?

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

14

How do adaptive immune cells recognise antigens?

B cells/Abs detect BCR directly

T cells detect MHC on antigen presenting cells

15

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

Central Tolerance:
T = Thymus
B = Marrow

Peripheral Tolerance:
- 2nd lymphoid organs & circ

16

What happens during central tolerance?

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

How does peripheral tolerance work?

Regulatory T cells destroy self-reactive lymphocytes

18

What are the major types of T cells?

Cytotoxic (CD8+)
Helper (CD4+)
Regulatory

19

What do CD8+ T cells do?

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

20

What do CD4+ T cells do?

Helper:
Activate B cells

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

21

Which type of Th cell attacks which type of pathogen?

Th1 targets intracellular pathogens

Th2 & Th17 target extracellular pathogens

22

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

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

Suppress Th & cytotoxic T cells

23

Which immunoglobulins are monomers, dimers & pentamers?

Monomer - IgG, IgE, IgD

Dimer = IgA

Pentamer = IgM

24

Which immunoglobulin can cross placenta?

IgG

25

Which immunoglobulin is involved in parasites and allergies?

IgE

26

Which antibody activates complement?

IgM

27

What are the functions of immunoglobulins?

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

28

What are the major causes of Secondary Immune Deficiency?

Environmental e.g. malnutrition or trauma

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

Drugs e.g. Glucocorticoids, cyclosporin or Rituximab