Anti-parasitic vaccines Flashcards
What is a vaccine?
A vaccine is a preparation of killed microorganisms, live attenuated microorganisms or subunits of microorganisms which are administered to produce or artificially increase immunity to a particular disease
Vaccines can work in two ways?
- To prevent infection
- To reduce the symptoms associated with infection
Are there currently any commercially available anti-parasitic vaccines for humans?
No
What vaccinations are available in animals?
Giardia vaccination in dogs
Tape worm vaccination in pigs
Vaccination against ticks in cattle
How many cases of malaria in 2015?
212 million cases
How many malaria associated deaths in 2015?
429,000 malaria associated deaths
Aside from the health burden malaria causes a large?
Economic burden
The economic burden can limit?
Economic prosperity
What is the economic burden of malaria in Africa?
Annual costs of $12 billion
Malaria accounts for how much of public health spending?
Accounts for 40% of public health spending
Countries incur costs due to?
- Malaria eradication programmes
- Cost of treatment
- Cost of drugs
- Cost of days lost from work
- Cost of school absenteeism and reduced development of children due to the disease
- Loss of worker productivity
- Reduction in fertility and population growth
Current malaria control methods?
- Drugs
- Insecticides
- Indoor residual insecticide spraying
- Nets with pyrethoid insecticides
What is an example of an anti-malarial drug?
Artemisinin
What was the GMEP?
Global Malaria Eradication Programme
When was the GMEP established?
1955
What did the GMEP involve?
- Antimalarial drugs
- Spraying DDT insecticide
Benefits of the GMEP?
Eradication of malaria in 15 countries
Eradication of malaria in Europe from Italy, Portugal and Greece
Why did the GMEP not reduce the incidence of malaria in Africa?
- Logistically difficult to target
- Lack of funding
- Political instability
- High population density
- High incidence of malaria
What caused the GMEP to stop in the 1970s?
- Economic crisis in 1970s
- Could no longer financially support the programme
- Increased incidence of drug and DDT resistance emerging
When the GMEP stopped what occurred?
- Malaria resurgence occurred in many countries
When did the Global Malaria Eradication Programme begin?
1955
What is a vaccine?
A vaccine is a preparation of killed microorganisms, live attenuated microorganisms or subunits of microorganisms which are administered to produce or artificially increase immunity to a particular disease
What occurred in 1970s?
Economic crisis
GMEP halted
The halt of the GMEP led to?
Malaria resurgence in many countries
What is the vaccine technology roadmap?
To develop a vaccine with over 75% clinical protective efficacy by 2030
Developing vaccines by 2030 able to substantially reduce the transmission
What is the malaria vaccine technology roadmap?
This map outlines a path for the acceleration in malaria vaccine development
Aims of the malaria vaccine technology roadmap are to?
Have a vaccine by 2030 which can reduce the transmission of malaria and a vaccine with 75% protective efficacy against clinical malaria
Vaccines can be used against which life stages?
Pre-erythrocytic
Erythrocytic
Mosquito stage
Which vaccines are being developed to target the pre-erythrocytic stage?
RTS,S
Irradiated sporozoites
Which vaccines are being developed to target the erythrocytic stage?
AMA1
MSP1
Which vaccines are being developed to target the mosquito life stage?
Transmission blocking vaccines
Irradiated sporozoites are what type of vaccine?
Whole cell derived vaccine
AMA1, MSP1 and RTS,S are what types of vaccine?
Subunit vaccines
AMA1 is what protein?
It is released by the micronemes and is involved in cell attachment and invasion. It binds to the RON complex which is derived from the rhoptries and forms the tight junction
What is required to form the tight function?
AMA1 microneme protein
Rhoptry RON complex
RON?
Rhoptry associated neck protein
MSP1 protein?
This is a surface antigen which is distributed on the surface of the merozoite
What is RTS,S vaccine made up of?
Hybrid protein and AS01 adjuvant
Adjuvant in RTS,S?
AS01
What does each part of RTS,S stand for?
R= CSP repeats T= T cell epitopes S= Bound HBsAg S= Free HBsAg
What is CSP?
Circumsporozoite protein
What is the HBsAg and what is it required for?
It is a hepatitis B antigen
It is required for the formation of viral like particles
Where is CSP found?
Distributed evenly over the surface of the sporozoite. It is attached via a GPI anchor
What is the function of CSP?
It is a surface antigen/protein distributed over the surface of the sporozoite
It is involved in binding to the hepatocyte
It is highly conserved in Plasmodium species infecting humans
CSP is highly conserved in?
Plasmodium species infecting humans
CSP all you need to know?
Highly conserved in Plasmodium species infecting humans
Surface protein/antigen evenly distributed over the sporozoite surface
Involved in binding to the hepatocytes
Attached via a GPI anchor
Which is the most promising anti-malarial vaccine?
RTS,S
Issues with RTS,S?
- Not good in the long term, protection wanes over time
- Will not be able to achieve malaria eradication
It it worthwhile to implement RTS,S and why?
Cost effective even at the highest cost and lowest efficacy
What are issues with subunit vaccines?
Limited antigenic repertoire. The immunogen makes up a very small constituent of the entire parasite< 1%. May not elicit a strong enough immune response
