Complement receptor 3 mediates ruffle-like, actin-rich aggregates during phagocytosis of Leishmania infantum metacyclics.

Complement receptor 3 mediates ruffle-like, actin-rich aggregates during phagocytosis of Leishmania infantum metacyclics. Exp Parasitol. 2020 Aug 08;:107968 Authors: Dixit UG, Rodríguez NE, Polando R, McDowell MA, Wilson ME Abstract The parasitic protozoan Leishmania infantum resides primarily in macrophages throughout mammalian infection. Infection is initiated by deposition of the metacyclic promastigote into the dermis of a mammalian host by the sand fly vector. Promastigotes enter macrophages by ligating surface receptors such as complement receptor 3 (CR3), inducing phagocytosis of the parasite. At the binding site of metacyclic promastigotes, we observed large asymmetrical aggregates of macrophage membrane with underlying actin, resembling membrane ruffles. Actin accumulation was observed at the point of initial contact, before phagosome formation and accumulation of peri-phagosomal actin. Ruffle-like structures did not form during phagocytosis of attenuated promastigotes or during phagocytosis of the intracellular amastigote form of L. infantum. Entry of promastigotes through massive actin accumulation was associated with subsequent delay in fusion of the parasitophorous vacuole (PV) with the lysosomal markers LAMP-1 and Cathepsin D. Actin accumulation was also associated with entry through CR3, since macrophages from CD11b knockout (KO) mice did not form massive aggregates of actin during phagocytosis of metacyclic promastig...
Source: Experimental Parasitology - Category: Parasitology Authors: Tags: Exp Parasitol Source Type: research