Membrane knobs of unfixed Babesia bovis-infected erythrocytes: new findings as revealed by atomic force microscopy and surface potential spectroscopy

Atomic force microscopy (AFM) and surface potential microscopy (SPS) were used to examine the structure of the knobs of unfixed Babesia bovis-infected erythrocytes, AFM revealed each knob was found to consist of two subunits, components that have not been observed in chemically fixed knobs by transmission electron microscopy. In addition, SPS revealed the knob surface has a positive electrical charge and that the remainder of the erythrocyte surface has a negative charge. These factors might be central to the phenomenon of cytoadherence in cerebral babesiosis.