Brucella abortus Induces the Premature Death of Human Neutrophils through the Action of Its Lipopolysaccharide
Fig 5
Br-LPS released inside cells is mostly found within vacuolar compartments of PMNs.
Purified human PMNs 5 ×106 were infected with B. abortus 2308 at MOI 20. After one hour incubation, infected cells were fixed and processed for immunogold staining and electron microscopy. Detection of Br-LPS was performed using mouse IgG anti Br-LPS in combination with protein-A/protein-G colloidal gold 15 nm. (A) PMN (n, nucleus of cell) with intracellular B. abortus (white asterisk) and immunogold detection of Br-LPS. (B) and (C) correspond to amplified sections pointed with arrows from “A” panel; B. abortus (white asterisk) and immunogold detection of Br-LPS inside vacuoles (pointed by black arrow heads). (D) B. abortus (white asterisk) within a phagosome (ph) and vacuoles containing immunogold labeled Br-LPS (black arrow heads). (E) PMN membrane ruffle showing immunogold detection of Br-LPS associated to the membrane (white arrow heads) and B. abortus (white asterisk) debris inside a phagosome (ph) and immunogold detection of Br-LPS inside vacuoles (black arrow heads). No colloidal gold particles were observed when IgG purified from normal mouse serum was used for controlling the specificity of the reaction. Bar represents 500 nm.