IAH theme 3 Flashcards by Malaika Ahmed

Why is there a lag time with vaccines ?

required time to develop the priamry response that is specific

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What is special about the secondary immune response ?

it is antigenic

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Where do memory B cells develop ?

in lymph nodes

after primary immune response

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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

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What is IgA for ?

mucosa

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What are the characteristics of the secondary immune response ?

quicker

stronger memory T cells made

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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

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What is smallpox caused by ?

variola virus

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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

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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

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What was significant about cross immunity to cowpox ?

immunity against cowpox- cross reacting immunity via an antigenically related non pathogenically related virus

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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

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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

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What are the practical considerations for vaccines ?

low cost per dose
biological stability
ease of administration
few side effects

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What are the forms of vaccines ?

attenuated
killed
conjugate 
antigenically related but non pathogenic 
recombinant

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How can we kill organisms for vaccines ?

chemically
radiation
heated

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Why does chemically etc treating the pathogen allow ?

neutralise the pathogen
viral nucleic acids are susceptible
stop replication

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What are the disadvantages of killing microorganisms for vaccines ?

need large amounts of virus

might not be fully killed- insufficient

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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

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What are attenuated vaccines known as ?

live attenuated non virulent vaccines

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Give an example of an attenuated vaccine ?

measles

BCG

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What is the BCG vaccine and is it effective ?

vaccine against TB

effective in children not adults-

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How do attenuated viruses mimic natural infections ?

they mimic natural infections through their interaction with the immune response

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How do attenuated viruses interact with the immune response ?

they give better long lasting immunity

elicit CD4 and CD8 cells

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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