Fig. 4

Staining of immune cells in peritoneal wash from one representative N. meningitidis serogroup W (isolate PubMLST ID 57576) infected mouse, 3 h post-infection compared to a non-infected mouse. The defined immune cells are gated on the forward (FSC) and scattered (SSC) axis and are seen in red. These cells were then observed according to the specific phycoerythrin (PE) fluorochrome staining (FL2 axis) for macrophages (F4/80+), monocytes (Ly6C+), and neutrophils (Ly6G+), represented in black for both infected and non-infected mice. In the infected mouse, these cells were gated for apoptosis using FITC-labelled Annexin V (FL1 axis), which is represented by green colour. The percentage was calculated for gated cells from all the observed cells, which is indicated in each gate as well as the names of gated cells