FIGURE 4.

localization of Bc28.1 at the B. canis merozoite surface by immunofluorescence on live cells. Viability of B. canis merozoites assessed through fluorescent labeling with 6-carboxyfluorescein diacetate (6-CF) and the absence of propidium iodide labeling (two dead merozoites are positive in DAPI and propidium iodide, whereas five live merozoites are positive in DAPI and negative in propidium iodide). Rabbit anti-Bc28.1 serum was used to localize the protein on fixed merozoites (middle), showing a homogenous merozoite membrane pattern with internal structures labeled. On live merozoites (bottom panels), the observed pattern indicates the localization of Bc28.1 at the external side of the merozoite plasma membrane. Note the non-continuity of the labeling at the surface of merozoites. Control experiments with unrelated antibodies show no signal (data not shown). DIC, differential interference contrast.