Malaria-infected cells may latch onto healthy blood cells for protection

November 5, 2014, Agency for Science, Technology and Research (A*STAR), Singapore
Malaria-infected cells may latch onto healthy blood cells for protection
Malaria-infected red blood cells bind to uninfected red blood cells, forming structures called ‘rosettes’. Credit: A*STAR Singapore Immunology Network

The distinctive 'clumping' of blood cells that blocks vessels and causes tissue damage in malaria-infected patients is the focus of a multinational collaboration, which includes A*STAR researchers.

When malaria parasites are released into a host following a mosquito bite, they make their way into red (RBCs). In some cases, infected RBCs stick to uninfected RBCs—a phenomenon known as 'rosetting' (see image) leading to the formation of structures called rosettes. Studies of Plasmodium falciparum, the species responsible for the most malaria cases worldwide, suggest that rosetting either assists with the infection of new cells or acts as a shield against immune detection. The process can also contribute to certain complications associated with malaria.

Researchers led by Bruce Russell of the National University of Singapore recently set out to establish the function of rosetting in Plasmodium vivax, a less-well-understood species that nevertheless is responsible for almost 350 million cases of malaria per year. Laurent Renia, a collaborator on the study from the A*STAR Singapore Immunology Network, notes that the study of P. vivax relative to P. falciparum has been limited by the lack of robust experimental culture models. "P. vivax grows exclusively in reticulocytes, the young form of RBCs, which represent only 1 to 2 per cent of circulating RBCs in a normal person," he says. "In contrast, P. falciparum grows in normocytes, which are mature RBCs."

The researchers employed recently developed techniques for working with patient blood samples to analyze rosetting in P.-vivax-infected RBCs. They determined that cells infected by P. vivax and P. falciparum form rosettes with similar frequencies. Surprisingly, most P. vivax rosettes incorporated normocytes rather than reticulocytes, even though the latter cells are the preferred target of this species. "This mechanism was thought to facilitate the invasion of uninfected RBCs by reducing the distance between the parasite and the target cell," says Renia. "Instead, rosetting could help the parasite to escape the host immune system."

The researchers also learned details about how rosettes form. By using antibodies to block specific proteins on the surface of RBCs, they determined that a molecule called glycophorin C contributes to P.-vivax-mediated rosetting. Indeed, rosetting was rarely detected with RBCs lacking glycophorin C.

The other side of the puzzle remains unclear, however—the P. falciparum protein responsible for rosetting is absent in P. vivax, and Renia is now keen to uncover this missing molecule. "If we identify the parasite protein at the surface of the , we can try to develop a compound to block this interaction," he says.

Explore further: Understanding the diversity of immature red blood cells could help protect against malaria

More information: Lee, W.-C., Malleret, B., Lau, Y.-L., Mauduit, M., Fong, M.-Y. et al. "Glycophorin C (CD236R) mediates vivax malaria parasite rosetting to normocytes." Blood 123, e100–e109 (2014). dx.doi.org/10.1182/blood-2013-12-541698

Related Stories

Understanding the diversity of immature red blood cells could help protect against malaria

May 21, 2014
Red blood cells are released into the blood stream in their immature form—reticulocytes—from the bone marrow where they develop. Reticulocytes are important markers for certain blood disorders and infectious diseases ...

Study finds protein in platelets fight malaria but only for some people

December 7, 2012
(Medical Xpress)—Researchers in Australia have found that a protein in platelets found naturally in blood has a protective effect against malaria. In their paper published in the journal Science, the team describes how ...

Discovery may aid vaccine design for common form of malaria

January 9, 2014
A form of malaria common in India, Southeast Asia and South America attacks human red blood cells by clamping down on the cells with a pair of proteins, new research at Washington University School of Medicine in St. Louis ...

Brain-damaging complications of malaria arise from immune response to parasite antigens absorbed by blood vessels

September 11, 2013
Most deaths caused by the malarial parasite Plasmodium falciparum result from the onset of cerebral malaria. This severe neurological condition arises when parasites accumulate within the brain vasculature. Numerous studies ...

Why humans don't suffer from chimpanzee malaria

September 9, 2014
A genetic region responsible for red blood cell invasion was among a small number of areas found to differ between the genomes of malaria parasites that affect chimpanzees and Plasmodium falciparum, the parasite responsible ...

New research finds potential risk for millions in Africa believed resistant to vivax malaria

November 15, 2013
Provocative new research shows that the Plasmodium vivax parasite, responsible for nearly 20 million cases of malaria in 2010, may be "rapidly evolving" to overcome the natural resistance conferred by a blood type found in ...

Recommended for you

Clues to obesity's roots found in brain's quality control process

February 20, 2018
Deep in the middle of our heads lies a tiny nub of nerve cells that play a key role in how hungry we feel, how much we eat, and how much weight we gain.

Study looks at how newly discovered gene helps grow blood vessels

February 19, 2018
A new study published today found that a newly discovered gene helps grow blood vessels when it senses inadequate blood flow to tissues.

Scientists produce human intestinal lining that re-creates living tissue inside organ-chip

February 16, 2018
Investigators have demonstrated how cells of a human intestinal lining created outside an individual's body mirror living tissue when placed inside microengineered Intestine-Chips, opening the door to personalized testing ...

Data wave hits health care

February 16, 2018
Technology used by Facebook, Google and Amazon to turn spoken language into text, recognize faces and target advertising could help doctors fight one of the deadliest infections in American hospitals.

Researcher explains how statistics, neuroscience improve anesthesiology

February 16, 2018
It's intuitive that anesthesia operates in the brain, but the standard protocol among anesthesiologists when monitoring and dosing patients during surgery is to rely on indirect signs of arousal like movement, and changes ...

Team reports progress in pursuit of sickle cell cure

February 16, 2018
Scientists have successfully used gene editing to repair 20 to 40 percent of stem and progenitor cells taken from the peripheral blood of patients with sickle cell disease, according to Rice University bioengineer Gang Bao.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.