- Carbohydrate tags attached to viral proteins that help in
- These tags are key to successful liver infection and
transmission of parasite from host to another secondary vector (mosquito)
- The new discovery is of great interest for its
implications on improving malarial vaccine design and efficacy.
200 million people are affected with malaria every year and 6,50,000 die as a
result, there is no treatment or prevention measure that has higher odds. The
first malarial vaccine RTS,S was approved in 2015 and does not offer required
protection. The reason being that the malarial parasites are shape-changers and
evade immune detection. A research team at the Walter and Eliza Hall Institute has shown for the first time that carbohydrates on the surface of malarial parasites
play a vital role in its
ability to infect mosquitoes and humans. The study was published in Nature
of Carbohydrate Tags in Malarial Infection
Two steps in the malaria parasites life cycle
are crucial. One is the early stage of human infection, where the parasite
invades the liver of the host. The other is the later stage, where the parasite
is transferred to another mosquito from the human.
Study shows that the parasite tags its proteins
with carbohydrates to stabilize them and evade detection by the host immune
How does the New Finding Help Vaccine Design?
Despite decades of intensive research, there is
no commercially available vaccine against malaria. The only existing vaccine is
the RTS,S that was approved in 2015 against the most deadliest malarial
‘Interfering with the parasites ability to add carbohydrate tags, hinders liver infection and transmission to another vector.’
Currently vaccines are made by targeting the
viral coat proteins of the parasite. Upon vaccination, our body develops
antibodies against the viral proteins. If the vaccinated person is infected with
the same virus at a later point, the antibodies kill the parasite stopping
The currently available malarial vaccine, RTS,S
is only marginally efficient. One reason could be the fact that the until now
the carbohydrate tags over the viral proteins weren't taken into consideration
during vaccine design.
"Now that we know how important these
carbohydrates are to the parasite, we can be confident that the malaria
parasite cannot 'escape' vaccination pressure by doing away with its
carbohydrates." Dr Goddard-Borger, coauthor of the study, said.
"Interfering with the parasite's ability
to attach these carbohydrates to its proteins hinders liver infection and
transmission to the mosquito, and weakens the parasite to the point that it cannot
survive in the host." Dr Boddey, lead author of the study, said.
What Causes Malaria? Malaria
caused by Plasmodium parasites. These accumulate and spread to people through
an infected female mosquitoes. These mosquitoes are called the malarial vectors
since they carry the parasite and transmit it to people through bites. Out of
the 5 malarial species that cause malaria in humans, P. falciparum
pose the greatest risk.
- P. falciparum: most prevalent on the African continent, responsible
for most malaria-related deaths globally.
- P. vivax: dominant malaria parasite in most countries outside of
the sub-Saharan Africa.
- Malaria - (http://www.who.int/mediacentre/factsheets/fs094/en/)