Object recognition can drive motion perception

8 distinct phenomena. Antimalarial antibodies defined by agglutination, enzyme-linked immunosorbent assay (data not shown) or surface immunofluorescence (data not shown) were not associated with the presence or absence of infection. Anti-adhesion antibodies against CSAbinding parasites differ from antibodies against parasites with other binding phenotypes. In studies of CD36-binding parasites, sera were variably effective and blocked adhesion strain-specifically; the inhibition of adhesion may have been associated with agglutination, which can interfere with adhesion. Our data indicate that antiadhesion antibodies against CSA-binding parasites uniformly develop in multigravid women from holoendemic areas, appear in Asian and African women, block adhesion in a strain-independent manner, and are distinct from agglutinating antibodies. We have shown that women with antiadhesion antibodies against CSA-binding parasites are protected from malaria infection during pregnancy. Because women have limited exposure to the CSA-binding parasite before first gestation, primigravidas lack anti-adhesion antibodies against this parasite subpopulation. We propose that this absence of anti-adhesion antibodies increases susceptibility to malaria during first pregnancies. Further research is required to examine the association between anti-adhesion antibodies and pregnancy outcome, and, most important, to identify PfCSA-L as the next step towards developing a vaccine. An anti-adhesion vaccine that conferred protection against maternal malaria would benefit millions of pregnant women and infants in the tropics, and should be a public health priority. Michal Fried*, François Nosten†, Alan Brockman†, Bernard J. Brabin‡, Patrick E. Duffy* *Department of Immunology, Walter Reed Army Institute of Research, 14th and Dahlia Street, Washington DC 20307, USA e-mail: [email protected] †Shoklo Malaria Research Unit, PO Box 46, Mae Sot, 63110, Thailand; Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; and Centre for Tropical Medicine, Nuffield Department of Medicine, John Radcliffe Hospital, Oxford OX3 9DU, UK ‡Tropical Child Health Group, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK