Editors' ChoiceHost-Pathogen Interactions

Platelets Poison Parasites

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Science Signaling  11 Dec 2012:
Vol. 5, Issue 254, pp. ec316
DOI: 10.1126/scisignal.2003852

Activated platelets bound to malaria parasite–infected red blood cells were once thought to contribute to pathogenesis, but recently the platelets have been found to have a protective effect. McMorran et al. (see the Perspective by Engwerda and Good) extended this discovery to show that platelet activation releases intracellular granules containing a chemokine, PF4, which is internalized by Plasmodium falciparum–infected red cells. Subsequently, mature parasites within the cells die. The Duffy blood-group factor on red blood cells is known to act as a nonspecific receptor for chemokines, such as PF4, as well as a receptor for cell invasion by other species of malaria parasite. When the Duffy antigen was blocked by antibody treatment, platelets and PF4 were less able to kill the P. falciparum parasites within.

B. J. McMorran, L. Wieczorski, K. E. Drysdale, J.-A. Chan, H. M. Huang, C. Smith, C. Mitiku, J. G. Beeson, G. Burgio, S. J. Foote, Platelet factor 4 and Duffy antigen required for platelet killing of Plasmodium falciparum. Science 338, 1348–1351 (2012). [Abstract] [Full Text]

C. R. Engwerda, M. F. Good, Platelets kill the parasite within. Science 338, 1304–1305 (2012). [Abstract] [Full Text]