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Newly discovered antibodies 'nip' malaria in the bud

Date:
March 19, 2018
Source:
Università della Svizzera italiana
Summary:
Scientists have discovered a new class of antibodies that potently block malaria parasites in the initial phase of the infection thus, conferring a sterilizing immunity. These antibodies bind to the surface of the sporozoites, the infectious form of the malaria parasite which is injected into the blood by the mosquito.
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A Swiss team of researchers from the Institute for Research in Biomedicine (IRB), affiliated to the Università della Svizzera italiana, and from the Swiss Tropical and Public Health Institute (SwissTPH), associated Institute of the University of Basel, has discovered a new class of antibodies that potently block malaria parasites in the initial phase of the infection thus, conferring a sterilizing immunity. These antibodies bind to the surface of the sporozoites, the infectious form of the malaria parasite which is injected into the blood by the mosquito.

The new study describes antibodies able to directly neutralize the parasites injected by the mosquito and therefore to stop the infection in the bud. This work, published in the scientific journal Nature Medicine, was carried out in collaboration with researchers at the Scripps Research Institute in La Jolla and the Center for infectious disease research in Seattle and was partially funded by the Swiss National Science Foundation (SNSF), the European Research Council (ERC), Swiss Vaccine Research Institute and the Fondazione Aldo e Cele Daccò.

The most lethal form of malaria is caused by the protozoan parasite Plasmodium falciparum, which is responsible for approximately 400,000 deaths yearly. Only a small number of Plasmodium parasites (10-100) is delivered during each infectious mosquito bite. These Plasmodium parasites, also called sporozoites, quickly reach the liver where they expand and give rise to a massive infection of the red blood cells that causes a severe pathology. Antibodies can therefore protect at two levels: in the initial phase, by blocking sporozoites, and in the acute phase of the disease, by blocking the infected red blood cells. The same Swiss team had reported, in two papers published previously in the journal Nature, a new molecular mechanism that generates broad-spectrum antibodies able to bind red blood cells infected by the parasite and therefore to keep the infection under control.

A portion of the surface protein of sporozoites (CSP) is the basis of the current vaccine (RTS, S), which unfortunately has only a modest effectiveness in preventing the infection. For this reason, experimental vaccines based on attenuated whole parasites were tested. The Swiss team isolated a series of monoclonal antibodies from individuals who were protected from one of these experimental vaccines (Sanaria PfSPZ Vaccine) and found that the most effective antibodies recognized a distinct region within the surface protein of the sporozoites that has not been considered in malaria vaccines so far. Further testing performed in Seattle revealed that these antibodies were highly potent in reducing malaria infection. In summary, this study has identified a novel part of the parasite surface protein that is a key target of inhibitory antibodies and represents a candidate for a second generation malaria subunit vaccine.


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Materials provided by Università della Svizzera italiana. Note: Content may be edited for style and length.


Journal Reference:

  1. Joshua Tan, Brandon K Sack, David Oyen, Isabelle Zenklusen, Luca Piccoli, Sonia Barbieri, Mathilde Foglierini, Chiara Silacci Fregni, Jessica Marcandalli, Said Jongo, Salim Abdulla, Laurent Perez, Giampietro Corradin, Luca Varani, Federica Sallusto, Betty Kim Lee Sim, Stephen L Hoffman, Stefan H I Kappe, Claudia Daubenberger, Ian A Wilson, Antonio Lanzavecchia. A public antibody lineage that potently inhibits malaria infection through dual binding to the circumsporozoite protein. Nature Medicine, 2018; DOI: 10.1038/nm.4513

Cite This Page:

Università della Svizzera italiana. "Newly discovered antibodies 'nip' malaria in the bud." ScienceDaily. ScienceDaily, 19 March 2018. <www.sciencedaily.com/releases/2018/03/180319155952.htm>.
Università della Svizzera italiana. (2018, March 19). Newly discovered antibodies 'nip' malaria in the bud. ScienceDaily. Retrieved March 28, 2024 from www.sciencedaily.com/releases/2018/03/180319155952.htm
Università della Svizzera italiana. "Newly discovered antibodies 'nip' malaria in the bud." ScienceDaily. www.sciencedaily.com/releases/2018/03/180319155952.htm (accessed March 28, 2024).

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