IAH theme 3 Flashcards
Why is there a lag time with vaccines ?
required time to develop the priamry response that is specific
What is special about the secondary immune response ?
it is antigenic
Where do memory B cells develop ?
in lymph nodes
after primary immune response
What are the characteristics of memory B cells ?
high affinity
long lived
quisecent
already been through isotype switch and somatic hypermutation
class switched IgG
circulate and are more easily activated than naive B cells
What is IgA for ?
mucosa
What are the characteristics of the secondary immune response ?
quicker
stronger memory T cells made
What are the characteristics of Ab and T cell mediated immunity ?
Ab immunity is maintained in absence of the pathogen
T cell mediated immunity has a half life but does not significantly decrease
immunity is long lasting
What is smallpox caused by ?
variola virus
What was the original form of variolation ?
innoclation with virus from mildly diseased person
lead to mild disease and protective immunity but did kill some
Why does vaccination with cowpox confer immunity against smallpox ?
cowpox and smallpox share surface antigens
immunisation with cowpox induces antibodies against cowpox antigens
cowpox antibodies bind to antigens to neutralise smallpox virus
What was significant about cross immunity to cowpox ?
immunity against cowpox- cross reacting immunity via an antigenically related non pathogenically related virus
What is significant about the cross immunity method of vacciantion ?
most pathogens have no antigenically related non pathogenic counterpart
cant use as a vaccine basis
What are the features of effective vaccines ?
safe
protective- prevent illness
sustained protection- long lasting immunity
neutralising antibody- some pathogens in irreplaceable cells
protective T cells/B cells- intracellular pathogens require T cells
What are the practical considerations for vaccines ?
low cost per dose
biological stability
ease of administration
few side effects
What are the forms of vaccines ?
attenuated killed conjugate antigenically related but non pathogenic recombinant
How can we kill organisms for vaccines ?
chemically
radiation
heated
Why does chemically etc treating the pathogen allow ?
neutralise the pathogen
viral nucleic acids are susceptible
stop replication
What are the disadvantages of killing microorganisms for vaccines ?
need large amounts of virus
might not be fully killed- insufficient
How can we attenuate pathogens for use in vaccines ?
take the virus ans isolate it
grow in human cells and culture
infect into monkey cells
virus will mutate rapidly to adapt to monkey cells
virus no longer grows well in human cells
virus is now attenutated
use as a vaccines
What are attenuated vaccines known as ?
live attenuated non virulent vaccines
Give an example of an attenuated vaccine ?
measles
BCG
What is the BCG vaccine and is it effective ?
vaccine against TB
effective in children not adults-
How do attenuated viruses mimic natural infections ?
they mimic natural infections through their interaction with the immune response
How do attenuated viruses interact with the immune response ?
they give better long lasting immunity
elicit CD4 and CD8 cells
What is different about attenuated and live viral particles ?
attenuated viral particles cannot produce cytosolic particle so cant be presented by MHC class I
Give some diseases that utilise bacterial toxins ?
diptheria
cholera
tetanus
What do vaccines against toxins consist of ?
inactivated toxins
How do we produce a recombinant HepB vaccine ?
isolate the hepB antigen gene
insert into the yeast genome
place genome into cell and brew in large numbers
production of recombinant protein by yeast
use antigen in vaccine when purified
How do pathogens mainly enter the body ?
through mucosal surfaces
How are most vaccines administered ?
injection IV
What are the routes of administration of a vaccine ?
intra nasal
oral
What do vaccines via injection induce ?
systemic antibodies
do not prevent all mucosal symptoms
Why might mucosal immunisation be better ?
induces mucosal antibodies
more effective agaisnt the disease
What are the disadvantages of administering vaccines by injection ?
can lead to systemic side effects
requires training
Give an example of an encapsulated bacteria ?
haemophilius influenza type b- causes meningitis
Which complement activation pathway induces antibodies ?
classical
induces IgG and IgM
use against encapsualted bacteria
What do capsular subunit vaccines consist of and what do they give rise to ?
consist of polysaccharide capsule only
gives rise to thymus independent response
only IgM made
What is the problem with only IgM being made ?
weak immune response no class switching no somatic hypermutation no memory might be ok for adults but elderly and children need T cell mediated immunity
Which type of vaccine do we use for encapsulated bacteria ?
conjugate vaccine
What do conjugate vaccines consist of ?
specific polysaccharide antigen which is chemically coupled to carrier protein like tetanus toxin
What do conjugate vaccines allow ?
conversion of polysaccharide into T cell dependent antigen
stimualtes CD4 cell response and allows B cell help
What is the problem with purified pathogen antigens ?
they dont give a good innate response
we need the innate response to activate the immune response - APC activate T cells
What are adjuvants ?
susbtances added to vaccines to encourage inflamamtion
Give some examples of adjuvants ?
alum salts
squalene oils
What do adjuvants do ?
induce sterile inflamamtion by interacting with NLRs
mimics what happens in natural infections
What do mother mucosal surfaces do in passive immunity ?
dimeric IgA from the mucosa to the baby in mothers milk
Which antibody can pass across the placenta and privode in utero and post partum immunity ?
IgG
When does immune system fully develop ?
4/5 years old
When does the adaptive immunity start to fucntion ?
6 months
What is another example of passive immunity ?
anti sera
given in response to snake/spider venom
What is the concept of herd immunity ?
if majority of population have protective immunity so the susceptible minority are protected
lower chance of the microorganism finding a non immune host - lower chance of infection
What happens if there are more non immune people in the popualtion ?
greater likelihood of outbreaks and pandemics
What is in the 6 combi vaccine given to babies under 1 ?
diptheria HepB Hib polio tetanus whooping cough
What is Hib ?
haemophilia influenza b
Which vaccine is given to children aged 1-15?
MMR
HPV
Which vaccines are given to adults ?
flu
shingles
Which vaccines are given to at risk people ?
BCG
HepB
What is SSPE ?
subacture scleorsing panencephalitis
late consequence of measles infection
leads to CNS problems
How does measles spread ?
cough , sneeze droplets
What are symptoms of measles ?
cold fever tiredness loss of appetite RASH KOPLIKS SPOTS on buccal mucosa
What are the complications of measles ?
encephalitis
meningitis
hepatitis
What are rash-kopliks spots ?
early sign of measles
What is a key disease elimination indicator ?
vaccine coverage
Which people do measles deaths occur in ?
immunosupressed
unimmunised
leukaemia patients in remission
What does measles infection do ?
infect leukocytes- causes immune supression
reduce immune memory against infleunza and herpes
What does measles induce ?
immune amnesia - disrupts immune recognition
not found in MMR vaccinated children
What is social demography ?
relationships between economic, social and cultural biological processes influencing a population
What are the strengths of vaccines ?
experience and understanding
immunology, microbiology and molecular biology
What are the weaknesses of vaccines ?
difficult to develop vaccines against some diseases that mutate rapidly like HIV and Influenza
What are the threats of vaccines /
social demography reduces uptake
What is the pathway to vaccine effectiveness ?
research
development
implement
maintenance
What needs to be considered in the research phase of vaccine development ?
epidemiology- route, spread and demographics
microbiology- rates, replication and genome
immune system- T cell mediated/antibody mediated, key antigens
What happens in the development phase for vaccine development ?
adequate research/studies
route of immunisation needs to be discovered
formulation- adjuvants, combinations
production capacity and economics
What are personal views that can compromise vaccine effectiveness ?
fear of the unknown/misconception social media/anti-vaxxers mistrust ignorance of disease cost adverse publicity
What is the effect of fake news on vaccine effectiveness ?
ebola is mad eup
vaccines rewire DNA
healthier unvaccianted
mythical side effects
What are the demographic factors that compromise vaccine effectiveness ?
lack of healthcare infrastructure- teams/programs
country wide poverty
isolation of communities
secrtity
political issues- chinese hierarchy, insularity
ageing/obese children
porpus borders/,migration
