In vitro rosetting, cytoadherence, and microagglutination properties of Plasmodium falciparum-infected erythrocytes from Gambian and Tanzanian patients

Abstract

To understand the molecular mechanisms that lead to sequestration of red blood cells infected with mature stages of Plasmodium falciparum and to examine the relevance of earlier studies on adherence properties of laboratory-derived P falciparum parasites to the natural parasite population, we analyzed Gambian and Tanzanian isolates for in vitro cytoadherence and antibody-mediated microagglutination. Eighteen cryopreserved isolates of ring-stage parasites were cultured for 20 to 30 hours in vitro, in the patients original erythrocytes, to the trophozoite and schizont stage. All parasites were positive in the microagglutination assay with at least one of four African hyperimmune sera. In a rosetting assay, only 2 of the 18 isolates were strongly positive (35% and 41% of parasitized erythrocytes with more than two uninfected cells bound). Thirteen isolates showed either intermediate (5% to 18%) or low (less than 5%) rosetting while three isolates did not form rosettes. Infected cell-binding of the different isolates to immobilized CD36 or thrombospondin, or C32 melanoma cells correlated with the percentage of mature parasites in the blood samples (r = .932 for CD36, r = .946 for thrombospondin, and r = .881 for C32 melanoma cells). There was a high correlation between binding to CD36 and thrombospondin (r = .982). The extent of infected cell rosetting with uninfected cells in these blood samples was not correlated with these other receptor properties. We also observed coexpression of rosetting and cytoadherence receptors on the same parasitized erythrocytes.

Expression dynamics and physiologically relevant functional study of STEVOR in asexual stages ofPlasmodium falciparuminfection

“…However, both the extent and the strength of cytoadherence between the iRBC and endothelial cells were observed to be extremely low in physiological flow conditions. However, coexpression of rosetting and cytoadherence receptors on the same P. falciparum iRBC, as observed in some clinical studies (Hasler et al, 1990), suggests that an individual iRBC can express multiple surface ligands simultaneously. Other recent studies have also implicated certain members of STEVOR and RIFIN variant antigen families in mediating the rosetting of the P. falciparum parasite (Goel et al, 2015;Niang et al, 2014) in a PfEMP1-independent manner.…”

“…To test whether STEVOR proteins were capable of forming rosettes under flow conditions, microfluidics-based rosetting assays were established with R+ sets of 5A, A4, and A4(tr-I and II) clones. As the late-stage iRBC in P. falciparum sequester in blood vessels and disappear from circulation (Hasler et al, 1990;Rowe, Obiero, Marsh, & Raza, 2002), it is reasonable to assume that rosette formation in flow conditions is initiated around these adhered iRBC. Hence, a similar in vitro environment was replicated in our flow-rosetting assays.…”

Biological and Biochemical Characteristics of Cytoadhesion of Plasmodium falciparum -Infected Erythrocytes to Chondroitin-4-Sulfate

“…Almost all isolates bind in vitro to CD36 and thrombospondin (2,5,22,29), whereas only a few isolates adhere to ICAM-1, vascular endothelial cell adhesion molecule, E-selectin, platelet/endothelial cell adhesion molecule 1/CD31, and CSA (4,5,22,25,28,30). Many studies have found no correlation between the cytoadhesion phenotypes of field isolates and the severity of the disease (5,14,15,19,24,30). However, Ho et al found that cytoadhesion to C32 cells was associated with the severity of the clinical case (16), and Newbold et al found a correlation between adhesion to ICAM-1 and clinical illness in nonanemic patients and a particularly strong correlation in cerebral malaria patients (22).…”

A recombinant peptide based on Pf EMP‐1 blocks and reverses adhesion of malaria‐infected red blood cells to CD36 under flow

“…The role and relative importance of these different receptors in sequestration in vivo is not clear, however several lines of evidence indicate a central role for CD36. For example, PRBCs from malaria‐infected individuals from different geographical areas either bind more commonly or at higher levels to CD36 than to other receptors (Hasler et al ., 1990; Ho et al ., 1991; Ockenhouse et al ., 1991; 1992; Cooke et al ., 1995; Newbold et al ., 1997). In a number of studies, development of more severe clinical complications most closely correlated with increased adhesion to CD36 than to other receptors (Ho et al ., 1991; Ockenhouse et al ., 1991; Ringwald et al ., 1993).…”