Immunology Flashcards
1
Q
What is the role of the immune system?
A
- identify and eliminate microrganisms, harmful substances and abnormal cancer cells
2
Q
How can we manipulate the immune system?
A
- immunization
- anti-inflmmatory/immunosupression drugs
- cancer immunotherapy
3
Q
What is innate immunity
A
- present continously
- from birth
- non-specific
- quick response
4
Q
What is acqruired immunity?
A
- induced by prescence of foregin objects
- specific
- slower response
5
Q
What is the most important barrier to infection?
A
- the skin
6
Q
meaning of commensal?
A
- part of the normal floar
7
Q
explain phagocytosis?
A
- macrophages express PRR
- bind to PAMPs on pathogen
- form phagosome
- fusion with lysommones
- debris released
- MHC-11 display pathogen particles
8
Q
How can phagocytosis be enhanced?
A
- opsonisation
- cover the pathogen in soluble factors(opsins)
9
Q
Examples of opsonins?
A
- C3b
- IgG/IgM
- CRP
10
Q
What can a mast cell do?
A
- degranulation
- gene expression
11
Q
What are examples of pro-inflammatory substances?
A
- nitric oxide
- prostaglandis
- histamines
- pro-inflammatory cytokines
12
Q
Name 4 cells involved in innate immunity?
A
- macrophages
- mast cells
- neutrophils
- natural killer cells
13
Q
What can the complement system cause a cascade of?
A
- opsonization of pathogens
- direct pathogen killing
- acute inflammation
- leukocyte recruitment
14
Q
Explain the complement system
A
C3 --> C3b + C3a (by MBL) C3b binds to pathogen acts as a C5 convertase C5 --> C5b + Cba C5b binds to pathogen --> MAC (membrane attack complex)
15
Q
What acts as acute inflammation triggers in the complement cascade?
A
- C3a
- C5a
16
Q
Explain the process of neutrophil recruitment and initation
A
- proinflammatory mediators cause vasodilation and an increase in vascular permebility of the endothelial cells of blood vessels
- neutrophils margination and rolling
- binding to adhesion molecules (ICAM-1)
- transendothelial migration (diapedesis)
- chemotaxis
- phagocytosis, degranulation, NETs
17
Q
How are virally infected cells destroyed?
A
- release small proteins called interferons
- warn nearby cells of the presence of a virus
- induce apoptosis by natural killer cells
18
Q
What do natural killer cells do?
A
- kill virally infected cells and abnormal cancer cells
- by causing apoptosis
19
Q
Where do B cells mature?
A
- the bone marrow
20
Q
Where do T cells mature?
A
- the thymus
21
Q
What are B cells responsible for?
A
- producing antibodies that attack pathogens
- humoral immune response
22
Q
What are T cells responsible for?
A
- cellular immune responses
- CD4+ T cells (helper)
- CD8+ T cells (killer)
23
Q
Explain the structure of an antibody
A
- 4 polypeptide chains
- 2 x light chains
- 2 x heavy chains
24
Q
Where are the 2 primary lymphoid tissues?
A
- bone marrow
- spleen
25
What are plasma cells?
- produce and secrete soluble antigen specific antibodies
26
What are memory B cells?
- long lived cells that continue to circulate around the body
27
What 2 signals does a B cell recieve before it is activated?
- BCR binding
| - Th cell or PRR + PAMP
28
IgM? structure
- first Ig produced
| - pentamer structure
29
Functions of IgM
- aggultination
| - complement system activation
30
What is agglutination?
- clumping together to form an immune complex
- IgG and IgM
- enhances phagocytosis
31
What is the structure of IgG?
- Monomeric
32
What is the function of IgG
- 2nd to be produced
- most abundent Ig
- can be passed across the placenta
- agglutation
- opsonisation
- activating NK cells
33
IgD?
- Low levels
| - surface bound
34
IgA?
- 2nd most abundent
- monomeric in blood
- dimeric in breast milk
35
What 2 Ig can be passed from mother to infant?
- IgG (across placenta)
| - IgA (breast milk)
36
IgE?
- Triggers allergic responses
37
Explain the role of CD4+ T cells?
- key regulators of the entire immune system
38
Explain the role of CD8+ T cells?
- kill virally infected body cells
39
Explain the make up of a TCR?
- T cell antigen receptor
- membrane bound protein heterodimer
- composed of an alpha and beta chain
40
T cells can only recognise _____ antigens present to their TCR by _________
- T cells can only recognise peptide antigens present to their TCR by MHC molecules
41
What does MHC stand for and what are their roles?
- Major histocompatibility complex
| - displays peptide antigens to T cells
42
What are class I MHC molecules?
- expressed on all nucleated cells
| - present peptide antigens to CD8+ T cells
43
What are class II MHC molecules?
- only expressed on professional antigen presenting cells
| - present peptide antigens to CD4+ T cells
44
Examples of proffessional antigen presenting cells?
- dendritic cells
- macrophages
- B cells
45
CD4+ T cells release what growth factor?
- IL 2
| - Stimulates further proliferation of CD4+ T Th0 cells and increases CD8+ T cell proliferation
46
What do CD8+ T cell proliferate into?
- Cytotoxic T lymphocytes
| - kill virally infected cells
47
Function of TFH cells?
- germinal centre reaction
| - B cell co-stimulation
48
Function of TH1 cells?
- increases macrophage killing
| - releases pro-inflammatory cytokines
