The macrophage microtubule network acts as a key cellular controller of the intracellular fate of Leishmania infantum

Abstract

The parasitophorous vacuoles (PVs) that insulate Leishmania spp. in host macrophages are vacuolar compartments wherein promastigote forms differentiate into amastigote that are the replicative form of the parasite and are also more resistant to host responses. We revisited the biogenesis of tight-fitting PVs that insulate L. infantum in promastigote-infected macrophage-like RAW 264.7 cells by time-dependent confocal laser multidimensional imaging analysis. Pharmacological disassembly of the cellular microtubule network and silencing of the dynein gene led to an impaired interaction of L. infantum-containing phagosomes with late endosomes and lysosomes, resulting in the tight-fitting parasite-containing phagosomes never transforming into mature PVs. Analysis of the shape of the L. infantum parasite within PVs, showed that factors that impair promastigote-amastigote differentiation can also result in PVs whose maturation is arrested. These findings highlight the importance of the MT-dependent interaction of L. infantum-containing phagosomes with the host macrophage endolysosomal pathway to secure the intracellular fate of the parasite.

Intranasal vaccine from whole Leishmania donovani antigens provides protection and induces specific immune response against visceral leishmaniasis

“…Leishmania donovani (MHOM/ET/67/HU3, known as LV9) promastigotes, were cultured in M199 medium (Gibco, Invitrogen) supplemented with 0.1 mM adenosine, 5 μg/mL hemin, 25 mM 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES), 25 mM NaHCO 3 (Sigma-Aldrich), and 10% heat-inactivated fetal bovine serum (FBS) (Gibco, Invitrogen). Promastigotes were maintained at 25°C, neutral pH, in a dark environment under an atmosphere of 5% CO 2 [ 23 , 24 ]. For infection, mice were injected with 10 3 promastigotes at the stationary phase of growth, via the intradermal (ID) route [ 25 , 26 ].…”