vaccinations and immunisation Flashcards
what are the 6 different types of vaccine?
- Live
- Attenuated
- Killed
- Extract
- Recombinant
- dna/Mrna
what is the Pasteur Principle?
ISOLATE pathogen
INACTIVATE pathogen
INJECT people with vaccine.
what are the 6 essential characteristic of vaccines?
1 - must provide protection without risk of causing the disease or severe side effects
2 - protection should be long lived
3 - should stimulate correct immune response
4 - stimulate neutralising antibodies to prevent re-infection.
5 - stable for long term storage and transport
6 - economically affordable for widespread use.
Live vaccine
organisms capable of normal infection and replication. not used against pathogens that can cause severe disease.
attenuated vaccine?
organism is live, but ability to replicate and cause disease reduced by chemical treatment or growth addition in non-human cell lines (measles, mumps, rubella)
killed vaccine?
organism killed by physical or chemical treatment. Incapable of infection or replication, but still able to provoke strong immune response
extract vaccine?
materials derived from disrupted or lysed organisms, eg - capsular polysaccharides. used when risk of organism surviving inactivation steps
recombinant vaccine?
genetically engineered to alter critical genes. often can infect and replicate but does not induce associated disease.
DNA vaccine?
naked DNA injected. Host cells pick up DNA and express pathogen proteins that. stimulate immune response.
what vaccine is best and most likely to be used?
why is that?
what is the paradox?
live or attenuated
- paradoxically, the safer the vaccine the less effective it is going to be.
- living and attenuated organisms express proteins and stimulate the immune response in a manner which most closely resembles normal infection.
why have vaccination rates fallen?
there is huge herd immunity.
- the beneficial impact of vaccination is so clear that some people are not aware of the dangers anymore.
There is the possibility that not everyone needs immunised because there are enough people vaccinated that the chances of an unprotected person meeting a pathogen becomes small.
what is herd immunity?
a pool of unimmunised individuals that can become a victim to disease.
when a large part of the population of an area is immune to a specific disease
what is in the DTaP/IPV/Hib vaccine?
Men C vaccine?
DTaP/IPV?
Td/IPV?
1) Diphtheria, tetanus, pertussis, inactivated polio vaccine, heamophilus influenza type B.
2) meningococcal C conjugate
3) booster vaccine for diphtheria, tetanus, perstussis, polio.
4) booster vaccine for tetanus, diphtheria, polio.
what are the origins for:
HIV?
Ebola?
SARS?
vCJD?
HIV= non human primate origin
Ebola = handling of gorilla, chimp, duikers
SARS= palm civets and racoon dogs
vCJD= food chain, rendering
what do dendritic cells express?
what happens when CpG is included with HepB or flu vaccines?
patern recognition receptor (PRR), these are members of the toll-like receptor family.
DC sit on the interface between innate immunity and specific immunity.
Activation of DC’s increase the their ability to capture and process antigen and immunogens, and also attract and activate T cells.
When CpG is included with herb or flu vaccines the result os increased antibody or INF-y secretion.
describe the stages of the activation of dendritic cells?
1- encounters antigen in periphery, becomes activated
2- migrates to lymph node
3- activates T cells to become effector cells.
when are pneumococcal and flu vaccine offered?
- the pneumococcal vaccine is offered to 65yrs and over
- flu vaccine is offered to the elderly and at risk individuals. in the region of 11 million people are within the recommended group.
when are travel vaccinations changing?
what are 3 examples of travel vaccination recommendation from 2005?
Travel vaccinations are constantly changing
3 examples of travel vaccination recommendations from 2005:
1) Avian Flu, West Nile Virus (USA, Canada and Portugal)
2) Marburg Virus (Angola)
3) Poliomyelitis (Nigeria)
What is reverse vaccinology?
Why was this useful for meningococcus B?
- Reverse vaccinology is the technique of identifying the protein exposed on the surface of pathogens by sequencing their genome in order to find new vaccines
- Originally, the microorganism itself was used to create vaccines
- This is useful for Meningococcus B, because the capsular polysaccharide antigen that would normally be a good target looks almost identical to a sugar on NCAM, an important neuronal membrane protein.
- Antibodies could cause autoimmunity due to this
what are examples of challenges in development of vaccination?
Examples of challenges in development of vaccinations:
1) 1918: Spanish Flu, 20-40 million dead
2) 1957: Asian Flu, 1-4 m dead
3) 1968: Hong Kong, 4m dead
4) Latest potential threat is H5N1.
* First reappeared HK 1997, infected 18, killed 6.
* Multiple cases in Far East
* 100 million fowl culled to prevent spread.
5) SARS coronavirus: Feb to July 2003
* infected 8,098 people, killed 774.
6) West Nile Virus: NY 1999
* Within 4 years spread across most of USA, infected 9,862 people, 264 deaths in 2003
What do vaccines have to engage in the immune system?
What do dendritic cells express?
How do dendritic cells work?
It is important that there is a strong dendritic cell activation in the immune system from vaccines
Dendritic cells express Pattern Recognition Receptors (PRR), members of the Toll-like receptor Family (TLR)
When dendritic cells meet something pathogenic, they grab a hold of the pathogen, and move it to the lymph node to start the process of activating T and B cells
This results in a big upregulation of the immune response
Are dendritic cells (DC) innate or adaptive immunity?
What does activation of DCs increase?
What is CpG?
What does it help stimulate? What is IFN gamma?
Dendritic cells (DC) sit at the interface between innate immunity and specific (adaptive) immunity
Activation of DC’s vastly increases their ability to capture and process antigen and immunogens, and also attract and activate T cells.
CpG is an adjuvant that can be used in HepB or flu vaccines
When used, it helps stimulate increase antibody production of IFN-gamma secretion
Interferon‐gamma (IFN‐γ) is a cytokine that plays an important role in inducing and modulating an array of immune responses
