Abstract

African trypanosomes are flagellated extracellular parasites, causal agents of African trypanosomiasis. Trypanosoma brucei is the most frequent species for the majority of African trypanosomiasis. Two sub-species are pathogenic for humans: Trypanosoma brucei gambiense and Trypanosoma brucei rhodesiense while Trypanosoma brucei brucei is not.

Objective: The aim of this work was to study the infectivity of Trypanosoma brucei brucei, on human microglial cells (CMH-5).

Methods: Trypanosomes (Trypanosoma brucei brucei Antat 1.9) labeled with a fluorescent dye were co-cultured with CMH-5 cells for 3 h. The nucleus and cytoskeletal microtubules of the cells were then labeled with two fluorescent dyes and the stained cell layer was examined by confocal microscopy.

Results: Trypanosomes were observed within CMH-5 cells.

Conclusion: Trypanosoma brucei brucei, a non-human parasite and described as an extracellular parasite, appears to have the ability to enter in human microglial cells in vitro. This raises a number of issues concerning the behaviour of this parasite in the human CNS and the immune response initiated by microglial cells which corresponds to endogenous defenses of the human brain.

Keywords: African trypanosomiasis; Trypanosoma brucei brucei; Human microglial cell; Intra-cellular parasite; Confocal microscopy