Cells were then washed and cultured in erythroid proliferation medium  consisting of IMDM with 330 μg/ml iron-saturated human transferrin and 10 μg/ml recombinant human insulin, supplemented with 5% heparinized human plasma, 100 ng/ml stem cell factor (SCF) (Cambridge Biosciences, Cambridge, UK), 5 ng/ml interleukin-3 (IL-3) (R&D Systems, Minneapolis, MN, USA), 3 U/ml EPO and 10−6 M hydrocortisone for 1–2 days. CD34+
Protein Tyrosine Kinase inhibitor cells were plated directly into the appropriate conditions. Manual cell counting was performed using the trypan blue exclusion method with trypan blue diluted 1/6 in phosphate buffered saline (PBS) and added to cells at 1:1 or 1:4 ratios. P. falciparum-conditioned medium was obtained from blood-stage cultures 26s Proteasome structure of P. falciparum 3D7 cultures grown in RPMI medium supplemented with 5% (wt/vol) Albumax® in a candle jar according to published methods . P. falciparum cultures were grown to 10–15% parasitemia, washed two times with wash medium consisting of RPMI supplemented with 0.18 g/l sodium bicarbonate and one time with IMDM and then resuspended in IMDM. For higher protein content, cultures were concentrated 6–8 fold by resuspension in lower volumes of IMDM after washing and cultured for 3–4 h to obtain conditioned
medium. Conditioned medium was obtained by centrifuging the culture supernatant for 10 min at 2000 rpm (823 × g) followed by filtration through a 0.2 μm filter and used at up to 80% (vol/vol) in erythroid medium. Cells (CD34+ cells or pre-cultured MNCs) were subsequently seeded in erythroid proliferation medium containing 5% heparinized human plasma, 100 ng/ml SCF, 5 ng/ml IL-3 and 3 U/ml EPO as standard conditions. These conditions served as a positive control for erythroid proliferation.
As a negative control, cells were seeded in pure IMDM medium lacking growth factors and plasma. Erythropoiesis inhibiting agents were added at different concentrations or growth factor concentrations were varied to assess the effect on erythroid proliferation. Cells were seeded in 96-well flat-bottom plates at 1–5 × 105 cells/ml and cultured in a humidified incubator also at 37 °C and 5% CO2 for up to 21 days. All conditions were set up in triplicate and for each condition a well containing the appropriate medium blank without cells was included. Absorbance measurements of plates with lid were taken at 405 nm using a Synergy H1 (Biotek, Potton, UK) plate reader preheated to 37 °C and following 2 min of linear shaking at 567 cycles per minute (cpm). Results from manual cell counting were determined as the mean and standard deviation of the cell concentrations of triplicate wells. Results from spectrophotometric measurements were determined as the mean absorbance of triplicate wells and their standard deviation.