Could the ingestion of 'modified' starch be a new malaria vaccine strategy?

Dec 23, 2010
Electron microscope image showing starch (white shell) containing a peptide of Plasmodium (black dots of gold particles) coupled with the GBSS of the green algae Chlamydomona. Credit:Stan Tomavo, CNRS

There is no efficient vaccine against malaria, although nasal and oral vaccination seems to be the most promising and suitable solution in countries where the parasite Plasmodium, which causes the disease, is rife. Researchers from two laboratories in northern France have successfully vaccinated and protected mice by feeding them starch derived from green algae and genetically modified to carry vaccine proteins. These encouraging results, which make it possible to envisage a simple and safe vaccination for children in countries at risk, are available online, on the scientific journal PloS One's website.

According to the WHO, malaria affects approximately 300 to 500 million people worldwide and kills one million each year, mostly young children. Insecticide-resistant carrying the disease and multi-drug resistant are on the increase. In this context, the development of a vaccine that alleviates symptoms and reduces mortality would be a valuable new tool in the fight against malaria. Researchers aim to test the efficacy of vaccine candidates among proteins that allow the parasite to penetrate host cells and infect them, in order to devise the best strategy for vaccine delivery.

Researchers from the Centre d'Infection et d'Immunité de Lille and the Unité de Glycobiologie Structurale et Fonctionnelle have developed a new vaccine strategy based on the ingestion of genetically modified starch. They used antigens that have shown their efficacy in “conventional” vaccinations as vaccine candidates. They fused these antigens to an enzyme (GBSS) in a starch granule from the , Chlamydomonas reinhardtii. This enzyme has the particularity of functioning inside the starch granule and of being protected, along with the antigens grafted to it, against degradation by other enzymes. In this way, the researchers were able to produce several murine and human antigens of Plasmodium within starch grains. These grains were then ingested by mice inoculated with the parasite. The researchers demonstrated that the mice were vaccinated by the starch grains, which significantly protected them against infection.

Starch is the insoluble and semi-crystalline polysaccharide that is the most commonly found in photosynthetic organisms. A starch grain can easily be produced from a plant extract and purified, in large quantities. It has a very stable structure and can be stored for months with no particular precaution, even if it undergoes temperature variations. It is easily assimilated through digestion and has a major ecological and financial interest, with very low production costs.

The starch of edible plants could be transformed in the same way as that of the algae Chlamydomonas reinhardtii. Researchers are thus looking at the possibility of using starch from multi-cellular algae used in Africa as a food supplement, but also from maize and potatoes. Administered to children under 3 years of age, who are at high-risk of malaria-related mortality, such plants could be both a food source and a vaccine. This strategy would allow simple vaccination, avoid storage problems and syringes, and thus eliminate potential HIV contamination.

The strategy based on the ingestion of genetically modified starch is protected by a patent.

The researchers now plan to test the efficacy of various Plasmodium antigens and determine whether such strategy can be applied to humans by verifying it has no side effects.

Explore further: US scientists make embryonic stem cells from adult skin

More information: PloS One, 15 December 2010: www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0015424 .

add to favorites email to friend print save as pdf

Related Stories

Breeding potatoes with improved properties

Nov 29, 2010

It is possible to breed potatoes in such a way that they produce new types of starch for use as a new and improved plant-based raw material in the construction, paper, glue, fodder and food industries. These ...

Vaccine hope for malaria

May 23, 2007

One person dies of it every 30 seconds, it rivals HIV and tuberculosis as the world’s most deadly infection and the vast majority of its victims are under five years old. Now, just over 100 years since Britain’s Sir Ronald ...

Spuds that like you -- in your summer salad

Jun 25, 2007

It has long been known that eating potatoes is good for bowel health, but new research suggests that they may also have a beneficial effect on the whole immune system. Especially if eaten cold or in a potato salad, Anne Pichon ...

Recommended for you

Leeches help save woman's ear after pit bull mauling

Apr 18, 2014

(HealthDay)—A pit bull attack in July 2013 left a 19-year-old woman with her left ear ripped from her head, leaving an open wound. After preserving the ear, the surgical team started with a reconnection ...

New pain relief targets discovered

Apr 17, 2014

Scientists have identified new pain relief targets that could be used to provide relief from chemotherapy-induced pain. BBSRC-funded researchers at King's College London made the discovery when researching ...

User comments : 0

More news stories

Cancer stem cells linked to drug resistance

Most drugs used to treat lung, breast and pancreatic cancers also promote drug-resistance and ultimately spur tumor growth. Researchers at the University of California, San Diego School of Medicine have discovered ...

Making graphene in your kitchen

Graphene has been touted as a wonder material—the world's thinnest substance, but super-strong. Now scientists say it is so easy to make you could produce some in your kitchen.