Host defence review

Question 1

what is the effect of common cold viruses

Answer 1

in 2009 swine flu pandemic 73% people infected but asymptomatic
pre-school children 6-10 colds a year
cause 17% GP consultations

Question 2

describe influenza

Answer 2

no re-infection by same strain
vaccine induced immunity rapidly wanes
homotypic immunity
annual vaccination required

Question 3

describe respiratory syncytial virus

Answer 3

recurrent reinfection with similar strains
no vaccine
poor immunogenicity
vaccine enhanced disease very active research field

Question 4

how is death a barrier

Answer 4

Wall of death protects internal and external surfaces

Question 5

list surface defences

Answer 5

commensal flora 
mechanical flow 
acids
mucous 
anti-microbial proteins

Question 6

lysozyme

Answer 6

splits bacterial cell wall

Question 7

lactoferrin

Answer 7

deprives proliferating bacteria of iron

Question 8

a-defensins

Answer 8

bactericidal, anti-viral

Question 9

B-defensins

Answer 9

bactericidal, antiviral

Question 10

secretory leukocyte protease inhibitor

Answer 10

bactericidal, anti-viral by blocking viral DNA synthesis

Question 11

cathelicidin

Answer 11

bactericidal, enhance mucin secretion

Question 12

what happens to specificity, breadth and learning as the sequence of the immune system progresses

Answer 12

specificity and learning increases

breadth decreases

Question 13

describe type 1 interferons

Answer 13

activate NK
upregulate MHC 
activate RNase L and PKR 
induces antiviral state 
produced by any nucleated cell - stressed by viral patterns

Question 14

describe type 2 interferons

Answer 14

interferon gamma
proinf
Th1 cytokine profile
‘immune interferon’

Question 15

defences against bacteria

Answer 15

surface defences 
Ab
complement - lysis/opsonisation 
phagocytosis 
release of inflammatory mediators and acute phase proteins  
fever

Question 16

defences against viruses

Answer 16

surface defences 
interferons 
inflammatory mediators and acute phase proteins 
NK cells 
antibody 
complement 
T cells

Question 17

what are the barriers to vaccination

Answer 17

political
social
economic
scientific

Question 18

ideal vaccine

Answer 18

safe 
easy to administer
cheap
stable 
active against all variants
life long protection

Question 19

characteristics of an eradicable infections disease

Answer 19

simple and cheap to diagnose
genetically stable 
accessible host species
eliminates persistant host, or persistently infected host cant transmit 
safe and effective vaccine