Purified N. caninum tachyzoites grown in vitro were added to
J774 and Vero cell lines. Before inoculation of parasites, host cells
were incubated for 24 h. The cultures were examined daily by
phase-contrast microscopy using an inverted microscope to determine
the presence of released tachyzoites. When 80–90% of the
host cells were disrupted and released a high concentration of
tachyzoites, the flasks were sharply tapped from the sides to release
the cells. The amount of tachyzoites harvested from each cell
culture type in the 5 ml of decanted supernatant was concentrated
by centrifugation at 500g for several minutes to eliminate the cell