the density of knobs on plasmodium falciparum-infected erythrocytes depends on developmental age and varies among isolates旋钮的密度在疟原虫falciparum-infected红细胞取决于发育年龄和分离之间的不同.pdf

The Density of Knobs on Plasmodium falciparum- Infected Erythrocytes Depends on Developmental Age and Varies among Isolates 1 1 1 1 2 3 Katharina A. Quadt , Lea Barfod , Daniel Andersen , Jonas Bruun , Ben Gyan , Tue Hassenkam , 2 1 Michael F. Ofori , Lars Hviid * 1 Centre for Medical Parasitology at i, Faculty of Health and Medical Sciences, University of Copenhagen and at Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark, 2 Department of Immunology, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana, 3 Nano-Science Centre, Department of Chemistry, Faculty of Science, University of Copenhagen, Copenhagen, Denmark Abstract Background: The virulence of Plasmodium falciparum malaria is related to the parasite’s ability to evade host immunity through clonal antigenic variation and tissue-specific adhesion of infected erythrocytes (IEs). The P. falciparum erythrocyte membrane protein 1 (PfEMP1) family expressed on dome-shaped protrusions called knobs on the IE surface is central to both. Differences in receptor specificity and affinity of expressed PfEMP1 are important for IE adhesiveness, but it is not known whether differences in the number and size of the knobs on which the PfEMP1 proteins are expressed also play a role. Therefore, the aim of this study was to provide detailed information on isolate- and time-dependent differences in knob size and density. Methodology/Principal Findings: We used atomic force microscopy to characterize knobs on the surface of P. falciparum- infected erythrocytes. Fourteen ex vivo isolates from Ghanaian children with malaria and 10 P. falciparum isolates selected in vitro fo