Immunofluorescence picture illustrating the effects of ALEXA-labelled Nb_An05 on AnTat1.1 parasites.

<p>A) Parasites were incubated at 4°C (upper right panel) and 37°C (upper middle panel). The morphology of trypanosomes kept at 37°C in the presence of Nb_An05 after 60, 90, 120 and 180 minutes incubation are shown. For each time point 10⁶ parasites were incubated with 1 µg Nb (VSG∶Nb ratio is 1∶4). B) Electron microscopy on sections of AnTat1.1 parasites incubated with Nbs for different time periods. Trypanosomes (10⁷) were treated with 10 µg of Nb_An05 or Nb_An33 (ratio VSG∶Nb equals 1∶4) or left untreated (NT: not treated) for the indicated periods, fixed and processed for EM. Images of ultrathin sections are shown. Nb_An05 causes enlargement of the FP. Scale bars are 500 nm, except in Nb_An05/0 min and Nb_An05/120 min panels where bars are 1 µm. Notice the accumulation of vesicles in the FP lumen and the enlargement of this compartment in Nb_An05 treated trypanosomes compared to Nb_An33 treated or untreated parasites. C) The average size of the FP transversal lumen surface, including the flagellum, after 60 minutes incubation in the presence (Nb_An05 (▴), Nb_An33 (○)) or absence of Nbs (▪). (**: p-value<0.005 and ***: p-value<0.0001).