PBMC are isolated from buffy coats by density gradient centrifugation using Biocoll (BIOCHROM).

Monocytes are isolated from PBMC using MACS anti-CD14 microbeads and a Midi-MACS® magnetic cell sorting device (both from Miltenyi Biotec, Bergisch- Gladbach,Germany).

Cells are subsequently separated into monocytes and lymphocytes by elutriation in a closed system (Elutra). The two most monocyte-rich fractions collected contained > 80% monocytes, the fraction richest in lymphocytes contained > 90% lymphocytes and viability in both fractions was > 95%.