Washington: Scientists at Heidelberg University Hospital have finally solved the mystery - why people with a hereditary mutation of the red blood pigment haemoglobin - as is the case with sickle-cell anaemia prevalent in Africa - do not contract severe malaria?
A degradation product of the altered hemoglobin provides protection from severe malaria.
Within the red blood cells infected by the malaria parasite, it blocks the establishment of a trafficking system used by the parasite’s special adhesive proteins – adhesins – to access the exterior of the blood cells.
As a result, the infected blood cells do not adhere to the vessel walls, as is usually the case for this type of malaria.
In the 1940s, researchers already discovered that sickle-cell anemia with its characteristic blood mutation was particularly prevalent in certain population groups in Africa. They also survived malaria tropica, whose course is usually especially virulent.
The scientists team headed by Prof. Michael Lanzer of the Department of Infectious Diseases at Heidelberg University Hospital compared the blood cells with normal haemoglobin and two haemoglobin variants (haemoglobin S and haemoglobin C), which occur in around one-fifth of the African population in malaria-infected areas.
In doing so, the scientists used high-resolution microscopy techniques such as cryoelectron tomography to discover a new transport mechanism.
The parasite uses a certain protein (actin) from the cytoskeleton (cellular skeleton) of the erythrocytes for its own trafficking network.
“It forms a completely new structure that has nothing in common with the rest of the cytoskeleton,” explained Dr. Marek Cyrklaff, group leader at the Dept. of Infectious Diseases, Parasitology.
“The vesicles with the adhesins reach the cell surface of the red blood cells directly via these actin filaments,” he said.
In contrast to erythrocytes with the two haemoglobin variants, here only short pieces of actin filaments are found. Targeted transport to the surface is not possible.
“With these results, we have now described a molecular mechanism for the first time that explains this haemoglobin variant’s protective effect against malaria,” Lanzer added.
The research study has been published in the journal Science, appearing initially online.
ANI
By clicking “Accept All Cookies”, you agree to the storing of cookies on your device to enhance site navigation, analyze site usage, and assist in our marketing efforts.
Cookies Setting
By clicking “Accept All Cookies”, you agree to the storing of cookies on your device and the processing of information obtained via those cookies (including about your preferences, device and online activity) by us and our commercial partners to enhance site navigation, personalise ads, analyze site usage, and assist in our marketing efforts. More information can be found in our Cookies and Privacy Policy. You can amend your cookie settings to reject non-essential cookies by clicking Cookie Settings below.
Manage Consent Preferences
Strictly Necessary Cookies
These cookies are necessary for the website to function and cannot be switched off in our systems. They are usually only set in response to actions made by you which amount to a request for services, such as setting your privacy preferences, logging in or filling in forms. You can set your browser to block or alert you about these cookies, but some parts of the site will not then work or you may not be able to login.
Functional Cookies
These cookies enable the website to provide enhanced functionality and personalisation. They may be set by us or by third party providers whose services we have added to our pages. If you do not allow these cookies then some or all of these services may not function properly.
Targeting Cookies
These cookies may be set through our site by our advertising partners. They may be used by those companies to build a profile of your interests and show you relevant adverts on other sites. They are also used to limit the number of times you see an advert as well as help measure the effectiveness of an advertising campaign. They do not store directly personal information, but are based on uniquely identifying your browser and internet device. If you do not allow these cookies, you will experience less targeted advertising.
Performance Cookies
These cookies allow us to count visits and traffic sources so we can measure and improve the performance of our site. They help us to know which pages are the most and least popular and see how visitors move around the site. All information these cookies collect is aggregated and therefore anonymous. If you do not allow these cookies we may not know when you have visited our site, and may not be able to monitor its performance.