Role of nonimmune IgG bound to PfEMP1 in placental malaria.

Infections with Plasmodium falciparum during pregnancy lead to the accumulation of parasitized red blood cells (infected erythrocytes, IEs) in the placenta. IEs of P. falciparum isolates that infect the human placenta were found to bind immunoglobulin G (IgG).

Rouleaux-forming serum proteins are involved in the rosetting of Plasmodium falciparum-infected erythrocytes.

Excessive sequestration of Plasmodium falciparum-infected (pRBC) and uninfected erythrocytes (RBC) in the microvasculature, cytoadherence, and rosetting, have been suggested to be correlated with the development of cerebral malaria. P. falciparum erythrocyte membrane protein-1 (PfEMP1) is the parasite-derived adhesin which mediates rosetting.

The time course of cytoadhesion, immunoglobulin binding, rosette formation, and serum-induced agglutination of Plasmodium falciparum-infected erythrocytes.

We describe morphologic characteristics of acridine orange-stained Plasmodium falciparum-infected erythrocytes and the sequential expression of several adhesion phenomena. In particular, we have studied when the adhesive and antigenic modifications appear on the infected erythrocyte surface that mediate binding to C32 melanoma cells (cytoadherence) or to erythrocytes (rosette formation) during a complete 48-hr life cycle of the parasite. The C32 melanoma cell binding started at about 12 hr and was seen during the whole life cycle with a peak around 28 hr (650 infected erythrocytes/100 C32 melanoma cells).

Extensive immunoglobulin binding of Plasmodium falciparum-infected erythrocytes in a group of children with moderate anemia.

Immunoglobulins (Ig) from healthy, nonimmune individuals bind to the surfaces of Plasmodium falciparum-infected erythrocytes (RBC). In order to investigate the presence of this parasite phenotype in wild isolates and its potential association with malarial anemia, we conducted a study of 207 anemic or nonanemic children with malaria in Gabon. Surface Ig binding to infected RBC was detected for 83% of the isolates.

Novel fibrillar structure confers adhesive property to malaria-infected erythrocytes.

Infections with the malaria parasite Plasmodium falciparum are characterized by sequestration of erythrocytes infected by mature forms of the parasite. Sequestration seems critical for the survival of the parasite, but may lead to excessive binding in the microvasculature and death of the human host. We report here that a novel electrondense fibrillar structure, containing immunoglobulins M or M and G, is found at the surface of infected erythrocytes that adhere to host cells.