Cd4 percp

Conjugated antibodies for surface staining CD3-APC, CD4-PercP, CD8-APC-H7, CD16-PercP, CD56-FITC, CD107a-PE-Cy7, NKp44-BUV395, and NKp46-BUV650 were purchased from BD Biosciences (San Jose, CA), whereas PD1-BUV650, NKG2A-PE, and NKG2C-Alexa Fluor700 were purchased from R&D Systems (Minneapolis, MN). Tregs cells were characterized by staining with CD4-PercP, CD25-PE-Cy5 and CD127-FITC (R&D Systems). CD4+ and CD8+ T cell subpopulations were determined by staining with CCR7-FITC and CD45RA-PE-Cy7 (Biosciences) as follows: naïve (CD45RA+CCR7+), central memory (TCM) (CD45RA-CCR7+), effector memory (TEM) (CD45RA-CCR7-) and terminally differentiated effector memory (TEMRA) (CD45RA+CCR7-) cells.
For intracellular staining of granzyme B (GZB) from NK and NKT cells, PBMCs were treated for 4 h at 37°C with Hsp70 peptide 1 µgr/ml (Abcam, Cambridge, UK) to stimulate cytolytic activity of NK cells, in the presence of brefeldin A (BD Biosciences). Cells were then stained with antibodies against CD3, CD56 and CD16 conjugated to APC, FITC and PercP, respectively. After fixation and permeabilization with IntraPrep Permeabilization Reagent (Beckman Coulter), cells were stained with an antibody against GZB-PE (BD Biosciences) and then acquired and analyzed in a BD LSRFortessa X-20 flow cytometer (BD Biosciences) using FACS Diva (BD Biosciences) and FlowJo_V10 software (TreeStar).