Fig 1.

Relationship between the percentage of infected macrophages and the β-lactamase activity of intracellular amastigotes. L. donovani transgenic promastigotes and L. donovani LV82 wild-type promastigotes were used to infect murine peritoneal macrophages. The percentage of infected macrophages was determined by Giemsa staining and microscopic analysis as indicated in Materials and Methods. The β-lactamase activity of intracellular L. donovani transgenic amastigotes (expressed as OD₄₉₀) was determined as described in Materials and Methods. Results represent the means and standard deviations of the results of three independent experiments. White bars, the percentage of infected macrophages with LV82; shaded bars, the percentage of infected macrophages with transgenic L. donovani promastigotes; solid squares, OD₄₉₀.