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Flashcards in L1 - Overview of Immune system Deck (14)
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1

ROLE OF THE IMMUNE SYSTEM

i) what is an antigen? 

ii) which part of the immune system is germline encoded eg cant be changed? which part is antigen specific?

iii) how does the innate immune system recognise antigens?

i) antigen is anything the immune system responds to

ii) GL encoded = innate
antigen specific = adaptive

iii) innate recognises antigens (PAMPs) by PRRs

 

2

CELLS OF THE IMMUNE SYSTEM

i) where are the cells initially produced? which cells are they produced from?

ii) which three cells are from a lymphoid lineage?

iii) name four cells from a myeloid lineage?

 

i) initially produced in the bone marrow from pluripotent haematopoietic stem cells

ii) lymphoid > T cells, B cells, NK cells

iii) myleoid > neutrophil, eosinophil, mast cell, RBC

3

CELLS WITH A MYELOID LINEAGE

i) what is the main function of a neutrophil? what is the appearance of the nucleus and the cytoplasm?

ii) which two cells are implicated in parasitic infections and allergic responses?

iii) what is the basophil tissue resident counterpart?

iv) what are monocytes called in the tissue? what name two roles

v) what are dendritic cells specifically for? 

i) phagocytosis
- multilobed nucleus and granular cytoplasm

ii) eosinophils and basophils

iii) basophil in tissue > mast cell

iv) monocytes in tissue = macrophages
- phagocytosis and antigen presentation 

v) dendritic cells are just for antigen presentation 

4

LYMPHOID LINEAGE 

i) what cells are they a similar size to? are they mostly cytoplasm or nucleus?

ii) which cells make antibody and do antigen presentation?

iii) what are the two types of T cells? what does each do? 

iv) what type of immunity are T and B cells involved in?

v) which immune system are NK cells part of? what do they do to infected cells?

i) lymphoid cells are a similar size to RBC
- little cytoplasm and big nucleus

ii) B cells make antibody and do APC

iii) T cells = Cd4 (help other components of immunity)
and CD8 (kill infected cells)

iv) T and B cells = adaptive immunity

v) NK cells part of innate immunity
- direct lysis of infected cells 

5

COMMUNICATION - CYTOKINES AND CHEMOKINES

i) what are cytokines? what are they important for?

ii) what is the main role of chemokines?

iii) what type of molecule are interleukins? 

iv) name three cytokines 

v) what forms the basis of seperating innate/adaptive immunity?

i) cytokines are small proteins released by cells that have an effect on another cell
- important in communication between immune/other cells

ii) chemokines main role is temporal and spatial organisation of cells and tissues 

iv) interleukins are cytokines

iv) TGFb, IFN-g, TNFa

6

INNATE ANTIGEN RECEPTORS

i) do they recognise specific antigens?

ii) which receptors do they use? what do these receptors recongise on target cells?

iii) how do cells of innate imm sys not recognise host cells?

iv) how are they encoded? what does this mean?

iv) is there clonal distribution 

i) do not recognise antigen specifically

ii) use PRRs that recognise PAMPs

iii) PAMPs are only seen in lower organisms 

iv) PRRs are germline encoded and same on every cell

iv) not clonally distributed 

7

MANNOSE BINDING LIGAND

i) what residues does it recognise? (2) 

ii) what pattern does it specifically look for on cells?

iii) why does MBL not bind host cells?

i) recognises mannose and fucose residues

ii) residues need to be on the correct spacing 

iii) MBL doesnt bind host cells as the residues are in a different spacing 

8

ADAPTIVE ANTIGEN RECEPTORS

i) do they recognise antigen specifically?

ii) name two adaptive receptors

iii) how are they produced? what does this therefore lead to?

iv) are they clonally distributed? what does this mean?

v) what two things do they permit?

i) yes

ii) B and T cell receptors

iii) produced through random somatic recombination between gene segments 
- leads to huge receptor diversity 

iv) yes they are clonally distributed - originally there is one copy of each receptor but as the cell divides it produces clones

v) permit specificity (ability to recog specific antigens) and memory (learning through clonal expansion - cells with receptors to antigens that have been previously encountered)

9

B CELLS 

i) which two forms can the B cell receptor (antibody) be in?

ii) what does the B cell receptor recognise?

iii) label A, B, C 

i) surface bound or secreted

ii) B cell R recognises intact antigen 

iii) A - variable region 
B - constant region 
C - light chain 

10

T CELL RECEPTOR 

i) is the receptor attached to the surface or secreted?

ii) what does it recognise?

iii) what two chains does it comprise of? 

i) cell surface receptor

ii) recognises processed antigen in the form of linear peptides

iii) alpha and beta chain 

11

GENERATION OF ADAPTIVE IMMUNE RECEPTORS

i) how are T and B cell receptors produced? which three gene segments does this involve? what does this result in?

ii) when are the most useful receptors selected?

iii) which two genes is the light chain made of? which three genes is the heavy chain made of?

iv) what is a disadvanatage of making receptors in this way?

i) produced by random recombination events 
- between V, D, J gene segments (all spliced together)
- results in huge receptor diversity 

ii) most useful receptors selected after birth on exposure to pathogens

iii) light chain = V+J
heavy chain = V+J=D

iv) disadantage = lots of receptors are junk 

12

T AND B CELL MEMORY 

i) on first exposure to an antigen - how long does it take to get a primary response?

ii) does the antibody level ever drop to baseline after primary exposure?

iii) what happens if the body meets antigen A again? 

iv) what happens to most clonally expanded T and B cells after primary infection? what happens to a few of them?

i) takes a few days to get a primary response

ii) never drops to baseline

iii) meet antigen A again > bigger and faster response 

iv) most clonally expanded T/B cells die off but a few remain as long lived memory cells 

13

CD8/CD4 T CELLS

i) what happens when a virus infects a cell?

ii) which MHC does CD8 T cell receptor recognise? 

iii) what are the only cell types that CD4 T cells respond to? give two examples

iv) which MHC is peptide presented on when recognised by CD4 cell? what needs to happen for CD4 to recog this?

i) virus infects cell > viral prots synthesised in cytosol > ER > viral fragments presented on MHC I 

ii) CD8 recognises viral presentation on MHCI 

iii) CD4 T cells only respond to antigen on APCs eg dendritic cells or B cells

iv) presentation of peptide on MHCII 
- CD4 needs the specific receptor for that antigen to recognise it 

14

ACUTE INFLAMMATION 

i) name four cardinal features

ii) name three blood vessel processes that underlie the process?

iii) what are clinical feaures defined by?

i) hot, painful, red, swollen

ii) vasodilation, adhesion molecules, increased permeability

iii) clin features defined by an interaction between pathogen and host immunity