Invasive forms of Toxoplasma gondii, Leishmania amazonensis and Trypanosoma cruzi have a positive charge at their contact site with host cells

We examined the surface charges of invasive forms of Toxoplasma gondii, Lei shmania amazonensis, and Trypanosoma cruzi by atomic force microscopy and s urface potential spectroscopy. We found that the specific part of the proto zoan which makes initial contact with the host cell is positively charged. This indicates that the positive charge at the site of contact facilitates binding of the invasive protozoan to negatively charged host cells.