The isolated PBMC (3 × 106/ml) were seeded in a 24-well flat bottom microplate and incubated with various concentrations (200–800 μg/ml) of selected fractions for 72 h. The cells were resuspended with cold PBS and were blocked with 1% bovine serum albumin in PBS for 5 min at room temperature. Then the cells were incubated with fluorescein isothiocyanate (FITC)-conjugated mouse anti-human CD4 and CD14, phycoerythrin-conjugated CD8, mouse IgG1 isotype for 30 min at 4 °C in the dark. After washing with PBS supplemented with 1% bovine serum albumin and 0.05% sodium azide, the cells were subjected to flow analysis. Expressions of CD4, CD8 and CD14 on 20,000 viable cells were then gated and analyzed by flow cytometry (Becton Dickinson FACSCanto II, USA).