Luciferase-expressing Leishmania infantum allows the monitoring of amastigote population size, in vivo, ex vivo and in vitro.

• Main Authors: Grégory Michel, Bernard Ferrua, Thierry Lang, Madhavi P Maddugoda, Patrick Munro, Christelle Pomares, Emmanuel Lemichez, Pierre Marty
• Format: Article
• Language: English
• Published: Public Library of Science (PLoS) 2011-09-01
• Series: PLoS Neglected Tropical Diseases
• Online Access: http://europepmc.org/articles/PMC3172198?pdf=render

Here we engineered transgenic Leishmania infantum that express luciferase, the objectives being to more easily monitor in real time their establishment either in BALB/c mice--the liver and spleen being mainly studied-or in vitro. Whatever stationary phase L. infantum promastigotes population--wild type or engineered to express luciferase-the parasite burden was similar in the liver and the spleen at day 30 post the intravenous inoculation of BALB/c mice. Imaging of L. infantum hosting BALB/C mice provided sensitivity in the range of 20,000 to 40,000 amastigotes/mg tissue, two tissues-liver and spleen-being monitored. Once sampled and processed ex vivo for their luciferin-dependent bioluminescence the threshold sensitivity was shown to range from 1,000 to 6,000 amastigotes/mg tissue. This model further proved to be valuable for in vivo measurement of the efficiency of drugs such as miltefosine and may, therefore, additionally be used to evaluate vaccine-induced protection.