The Effect of Hydrogen Peroxide on Leishmania amazonensis Promastigotes

Leishmaniasis is a disease caused by the parasite Leishmania. The disease causes lesions to the skin and face; when visceral it becomes fatal to its host. Leishmanias are transmitted through the female blood-sucking sand fly into its mammalian host, where it infects macrophages. Within the macrophages, Leishmania differentiates from a motile, rod shaped, nonvirulent promastigotes to a non-motile, spherical shaped, virulent amastigotes. Differentiation is due to the high temperature of the mammalian host body, in addition to the low pH of the macrophage. In vitro, the cells are differentiated in Graces medium (pH 5.3) at 33◦C. I investigated whether hydrogen peroxide induces differentiation in L. amazonesis. Four samples of L. amazonensis were tested, a wild-type 12-1, and three triple transfectants: DT-1 GFP, DT-2 GFP, and JP-2. The samples where incubated in 199-FBS medium with hydrogen peroxide concentrations ranging from 15mM to 500mM. The cells were stained and viewed under a brightfield microscope to determine if differentiation occurred. Some hydrogen peroxide concentrations killed the cells; no differentiation was obseved at the concentrations tested