QUESTION:
What information can you provide on this vaccine candidate?
ANSWER:
RTS,S is a vaccine candidate against Plasmodium falciparum malaria which works by encouraging the host’s body to produce antibodies and T cells which diminish the malaria parasite’s ability to survive and reproduce in the liver.
Produced by GlaxoSmithKline, RTS,S is the first vaccine candidate against Plasmodium falciparum that has reached advanced (Phase III) clinical field trials on a large scale. It was developed way back in 1987, and had successive trials in the United States in 1992 and then in Africa in 1998. In 2001, GSK and the Malaria Vaccine Initiative at PATH went into a public-private partnership, with grant money from the Bill and Melinda Gates Foundation, to develop the vaccine for use in children and infants in sub-Saharan Africa.
The Phase III trials are currently underway in a number of African countries; if all goes to plan, the vaccine will be submitted for regulation by drug authorities as early as 2012. This information, and more, can be found courtesy of the Malaria Vaccine Initiative website: http://www.malariavaccine.org/index.php.
WHAT IS THE MEANING OF RTS? WHAT IS THE MATERIAL USED IN RTS VACCINE ? HOW IT ACTS?
I am not sure what RTS stands for. The vaccine contains a genetically modified hepatitis B surface antigen virus-like particle, to which has been added part of the Plasmodium falciparum circumsporozoite antigen. The vaccine is administered together with an adjuvant which stimulates the immune response; together, the aim is to produce antibodies against the malaria circumsporozoite antigen, to prevent infection.
“A vaccine would complement and enhance existing measures to fight malaria, such as bed nets and indoor residual spraying,” Njuguna said.
The vaccine “RTS, S”, also called “RTS, S/AS”, is the most clinically advanced malaria vaccine in the world.
It is the first vaccine to demonstrate that it can protect young children (in 1994) and infants (in 2007) living in malaria endemic areas against clinical diseases and infection, caused by Plasmodium falciparum the most deadly species in the malaria parasites.
“RYS, S” is derived from the components parts of the antigen in the vaccine. Genetically modified yeast is used to produce the CS protein’s repeat region, which is represented by “R”.
The yeast is also programmed as protein represented by “T” that teaches T-cells to recognize malaria parasite. “S” stands for the hepatitis B antigen which is used to yield a high immune response.
The finals “S” represents the extras un-fused hepatitis B- antigen that is included to make the entire antigen on the parasite’s surface large enough to be noticed by immune system.
Many thanks for that info!
what is stands for RTS,S? I was search whole web about this but i didn’t got the RTS,S abbrevation please explain about RTS,S vaccine in molecular, biochemical level.
thank you.
Hi Sanjeev,
That’s a very good question. I know the vaccine works by combining Plasmodium falciparum circumsporozoite antigen with hepatitis B surface antigen. The circumsporozoite antigens promote the development of antibodies to this protein, which is integral to the parasite’s process of entering host red blood cells. However, I don’t know what the letters “RTS,S” stand for. I have contacted GlaxoSmithKline so hopefully they can enlighten us! I will post their response if and when they get back to me.
Many thanks,
– Claire, Managing Editor
Hi Sanjeev,
I have now heard back from GlaxoSmithKline. While they did not disclose the reason for naming their vaccine candidate RTS,S, they provided the following website link for more information about their product pipe-line. The product description called the vaccine “Mosquirix (Malaria RTS,S)” and describes it as a paediatric vaccine for Plasmodium falciparum prophylaxis.
I hope that has been of some help! Please let me know if you find more information about why the specific acronym RTS,S was used for naming this vaccine; I would be very interested to hear about it.
– Claire
Q:- which types the antign are produced in malaria ring & which the process the malarial ring is enterd in RBC( without break the RBCs)
The ring stage of malaria (also known as the trophozoite stage) possesses a number of different antigens (with many complicated names, such as R45, PFC0830w, etc), though it is actually not the infective stage – the trophozoites develop into schizonts, which burst, destroying the red blood cell and releasing many merozoites. It is these merozoites which invade the red blood cell. The details of this invasion process are very complicated biochemically, but basically involve four steps. The first is attachment; the merozoite possesses a specific organ, called the apical complex (which is also on other parasites related to malaria that invade red blood cells), which contains certain surface proteins which target specific membrane proteins on the red blood cell’s surface. Glycoproteins have been particularly observed to be important in the attachment process. Another important red blood cell surface receptor, specifically for Plasmodium vivax and Plasmodium knowlesi, is the Duffy antigen, which is a glycosylated membrane protein. People with mutations in this antigen (so-called “Duffy negative” people), which can occur through a variety of genetic changes, appear to be partially or fully resistant to infection by P. vivax and P. knowlesi. It was originally though, due to the Duffy antigen’s role in attachment for these malaria parasites, that resistance was conferred by the parasite not being able to invade the red cells, but more recent evidence has shown that the system may actually be much more complicated.
The second stage is the deformation of the red blood cell membrane, which radiates out from the point of attachement of the merozoite. After this, the merozoite actually invades the cell, which appears to be through a process similar to endocytosis (the red blood cell membrane seems to pull the merozoite into the vacuole. This process may mimic the natural process of iron uptake undertaken by young red blood cells as part of their normal development. Finally, the fourth step consists of further deformations to the red blood cell membrane which close up the area where the merozoite entered.
All of these steps were first observed using microscopy of animal malaria 50 years ago; more recently, improved microscopic and molecular techniques have revealed more of the detail.
What does the acronym RTS,S stand for?
RTS,S is a scientific name given to this malaria vaccine candidate and represents its composition. The ‘R’
stands for the central repeat region of the circumsporozoite protein (CSP); the ‘T’ for the T-cell epitopes of
the CSP; and the ‘S’ for hepatitis B surface antigen (HBsAg). These are combined in a single fusion protein
(‘RTS’) and co-expressed in yeast cells with free HBsAg. The ‘RTS’ fusion protein and free ‘S’ protein
spontaneously assemble in ‘RTS,S’ particles