Department of Microbiology, Faculty of Science, Mahidol University, Department of Clinical Tropical Medicine and Bangkok Hospital for Tropical Diseases, Faculty of Tropical Medicine, Mahidol University, Immunoparasitology Unit, The Walter and Eliza Hall Institute of Medical Research, Bangkok, Thailand
The association between cytoadherence of Plasmodium falciparum-infected erythrocytes and the severity of malaria has been evaluated. In this study, we investigate adherence to C32 melanoma cells, CD36, intracellular adhesion molecule-1 (ICAM-1), thrombospondin (TSP), E-selectin, vascular cell adhesion molecule-1 (VCAM-1), and chondroitin sulfate A (CSA) of 36 P. falciparum isolates from patients suffering from acute falciparum malaria. Adherence to purified adhesion molecules varied greatly among different parasite isolates. All isolates but one adhered to CD36, but none bound to E-selectin and VCAM-1 beyond control levels. Some P. falciparum isolates adhered to ICAM-1 and to CSA, a newly identified receptor for adherence. There was no correlation between in vitro binding to any one receptor and the patients' conditions. In addition, we investigated the characteristics of adherence to CSA and to C32 melanoma cells. Infected erythrocytes continued to adhere after trypsin digestion and soluble CSA inhibited adherence to C32 melanoma cells in a dose-dependent manner. The results imply a role for CSA in the natural infection of P. falciparum.