1. overview of immunology

Question 1

what is the main role of the immune system?

Answer 1

protect from infection

Question 2

what is an antigen?

Answer 2

anything the immune system responds to
usually a protein
not necessarily bad

Question 3

what is an antigen receptor?

Answer 3

recognises antigen
fundamental basis of immunity
basis of division into innate and adaptive immunity

Question 4

what is effector mechanism?

Answer 4

an action to respond to the antigen

Question 5

what is the difference between innate and adaptive immune systems?

Answer 5

innate = germline encoded, pattern-recognition receptors (PRRs)
adaptive = antigen-specific T and B cell receptors

Question 6

leukocytes from myeloid lineage

Answer 6

neutrophils 
eosinophils 
monocytes/macrophaes
dendritic cells
basophils/mast cells

Question 7

leukocytes from lymphoid lineage

Answer 7

b cells - adaptive
t cells - adaptive
nk cells - innate

Question 8

types of intracellular signalling

Answer 8

endocrine (hormonal - long distance)
paracrine (short distance)
autocrine (self signalling)
juxtacrine (membrane bound signal molecule)

Question 9

what are cytokines?

Answer 9

small proteins released by cells which have an effect on another cell

Question 10

what do cytokines do?

Answer 10

important for communication between cells of the immune system and between immune system cells and other cells/tissues

Question 11

what are chemokines?

Answer 11

have different structure, receptors and nomenclature to cytokines
important for attracting cells to site of inflammation

Question 12

what do chemokines do?

Answer 12

main role = temporal and spatial organisation of cells/tissues
chemo-attractants (induce chemotaxis)

Question 13

what are antigen receptors?

Answer 13

receptors that cells use specifically to recognise antigen
key in immunology
basis of separating innate and adaptive immunity

Question 14

innate antigen receptors key factors

Answer 14

do not recognise antigen specifically
pattens recognition receptors (PRRs) recognise pathogen associated molecular patterns (PAMPs)
genome encoded
not clonally distributed

Question 15

what is mannose binding lectin?

Answer 15

opsonin used in lectin pathway
binds to mannose and fructose residues on user face on many pathogens
residues must be present with correct spacing
targets cell for destruction

Question 16

classical features of innate immune receptors

Answer 16

work quickly
adaptive immunity takes more time to be activated
unable to ‘learn’
gremlin encoded, cannot change, no memory

Question 17

key features of adaptive antigen receptors

Answer 17

recognise antigen specifically 
t cell receptor, b cell receptor 
produced by random somatic recombination events between gene segments 
huge receptor diversity 
clonally distributed 
permit specificity and memory

Question 18

b cell receptors

Answer 18

(|antibodies)
may be surface bound or secreted
recognises intact antigen

Question 19

t cell receptors

Answer 19

very similar to b cell receptor
only present on cell surface (CD8 and CD4 t cells)
recognises processed antigen in form of linear peptides

Question 20

how are adaptive immune receptors produced?

Answer 20

somatic recombination events - between v, (d) and j segments
huge receptor diversity despite small number of genes
useful receptors selected after birth on exposure to pathogens

Question 21

t and b cell memory

Answer 21

after primary cell infection, most clonally-expanded t and b cell lymphocytes die off
few remain as long-lived memory cells

Question 22

how does clonal selection work?

Answer 22

1. large population of cells with different receptors
2. introduction of foreign antigen
3. receptors which bind to antigen are positively selected
4. cells with receptor for antigen are replicated rapidly

Question 23

examples of effector mechanisms

Answer 23

barriers (skin, acid pH)
cytokines 
complement 
phagocytosis 
cytotoxicity (CD8 T cell, NK cell)
antibody-dependent cellular cytotoxicity 
mast cell and eosinophil granulation

Question 24

how to CD8 t cells kill virally infected cells?

Answer 24

virus infects cell
viral proteins are synthesised in cytosol
peptide fragments of viral proteins bound by MHC class I in ER
bound peptides are transported by MHC class I to cell surface
CD8 T cells recognise peptide+MHC class I complex - kill cell

Question 25

cardinal features of acute inflammation

Answer 25

hot
painful
red
swollen 
describe process, not cause

Question 26

how does change in blood vessels underlie the process of acute inflammation?

Answer 26

vasodilatation
adhesion molecules
increased permeability