Direct Delivery

Science's STKE  05 Sep 2006:
Vol. 2006, Issue 351, pp. tw308
DOI: 10.1126/stke.3512006tw308


The life cycle of the malaria parasite in its mammalian host begins with a liver-specific stage, in which sporozoites delivered by the mosquito invade hepatocytes, where they develop into merozoites that invade red blood cells. Merozoites must enter the bloodstream, although precisely how they move from hepatocyte to the lumen of the liver sinusoid has remained a matter of speculation. In a study of a rodent form of the parasite, Sturm et al. reveal that, as the merozoites induce death of the hepatocyte, they simultaneously hold in check the normal cues that would signal phagocytosis of the dying cell. This alteration allows membrane-bound extensions of the infected cells, which the authors term merosomes, to bud off and shuttle the merozoites directly into the bloodstream. Thus, the parasites modify the host response to dying infected cells to ensure better survival and replication.

A. Sturm, R. Amino, C. van de Sand, T. Regen, S. Retzlaff, A. Rennenberg, A. Krueger, J.-M. Pollok, R. Menard, V. T. Heussler, Manipulation of host hepatocytes by the malaria parasite for delivery into liver sinusoids. Science 313, 1287-1290 (2006). [Abstract] [Full Text]

A. F. Cowman, S. H. I. Kappe, Malaria's stealth shuttle. Science 313, 1245-1246 (2006). [Summary] [Full Text]