In vitro cellular uptake Freshly isolated spelnocytes were incubated for 30 min at 4ºC with tLNPs (siCy5) followed by washing with PBS and incubation for 30 min at 37ºC to allow internalization. After, cells were stained with anti-CD4 PE and anti CD8-FITC. Cells were then analyzed by Nikon confocal microscope.