Ultrastructural analysis of USUV-infected cells reveals multiple organelles compatible with an autophagic response.

<p>Representative images of Vero cells infected with USUV SAAR 1776 (MOI of 5 PFU/cell) fixed and processed for transmission electron microscopy at 24 h p.i. (A) Electron dense virions located inside endoplasmic reticulum. (B) Vesicle packets (VP). (C) Endoplasmic reticulum-like structure wrapping around cytoplasmic material. Note the presence of VPs associated to the membranes. (D) Cytoplasmic portion showing a double membrane autophagosome-like vacuole (arrowheads) and a double membrane phagophore-like structure engulfing a cytoplasmic portion (arrows). Note also the presence of multi-lamellar structures. (E) Accumulation of multi-lamellar structures. (F) Double membrane vesicle (arrowheads) in association with a multi-lamellar structure. Nu denotes the cell nucleus. Scale bars: 100 µm.