Figure 5: Bioluminescence activity of intracellular Leishmania expressing episomal luciferase from infected macrophages in vitro. Recombinant L. infantum promastigotes overexpressing the secreted proteins pTEX-LinJ19.0410 () or pTEX-LinJ36.5780 ( ) were cotransfected with the pSP-YαHYGROαLUC carrying the firefly-luciferase gene. Survival of luciferase-expressing parasites was monitored in infected human monocyte cell line THP-1 differentiated into macrophages as indicated in the Methods section. Promastigotes transfected with the pTEX vector alone and the pSP-αHYGαLUC (□) were used as control for infection experiments. RLUs (Relative Luminescence Units) were measured at various time points post infection using the Steady Glo reagent. Results are expressed as the mean of three independent experiments, each carried out in triplicate.