Figure 5: Gating strategy for mass cytometry data.

After systemic administration of biological nanoparticles such as MNVs, splenocytes were isolated and stained with a cocktail of metal-conjugated antibodies, and mass cytometry was performed. Live single CD45⁺ events were identified by drawing a gate around the events that had high 191Ir staining and low levels of the 140 Ce metal tag to discriminate the cells from beads, bead-cell doublets, and debris. Next, a daughter population of the cell gate was created to identify single cells, which had moderate 191Ir staining compared to the doublets. Then a daughter population of the single cells was created to identify the live cells, which had low to moderate levels of 191Pt. Lastly, a daughter plot of the live single cells was generated to identify CD45⁺ events, which are expressed by all lymphocyte subtypes.