at contained medium only, from that of wells with cells. In order to monitor proliferation up to 72 hours, cells were seeded at a lower density to avoid any confluency in the cell monolayer and incubated in medium with 10 nM FK866 for 24, 48, and 72 hours. Plates were fixed and stained as described above. significance by applying a repeated measures analysis using PASW statistics 18 SPSS software. Three time frames of each FK866 curve were compared with the corresponding three time frames of the control curve. Scanning Electron Microscopy Cells were seeded on 12 mm glass coverslips in 24-well plates and treated with 10 nM FK866 for 3, 6, 15, or 24 hours. In addition, cells were activated with 100 ng/ml LPS or left nonactivated. Cells were washed once with PBS and fixed with 2% glutarealdehyde in 0.1 M sodium cacodylate buffer for 1 hour. After washing cells twice with cacodylate buffer, coverslips were stored in the same buffer at 4uC until further fixation with 1% OsO4 for 30 minutes. Coverslips were then washed once with water and dehydrated in a graded series of alcohol washes. Finally, coverslips were critical point dried and mounted for scanning electron microscopy. Cellular Actin Staining Cells on coverslips were incubated in control or FK866 medium for 24 hours and stimulated with 100 ng/ml LPS overnight or left unstimulated. Cells were washed twice with PBS and fixed in 2% paraformaldehyde in 0.2 M sodium phosphate buffer for 30 minutes. Coverslips were washed twice with PBS and twice with PBS containing 20 mM glycine before permeabilization with 0.1% saponine/PBS-G for 20 minutes. This was followed by actin staining with Alexa 568-labeled phalloidin for 1 hour. Cells were successively washed four times for 24 minutes with 0.1% saponine/PBS-G and once with PBS alone. Coverslips were removed from wells, rinsed once in water, air dried, and embedded in MoWiol on microscope slides. Z-scans consisting of 2560.5 mm sections with the pinhole adjusted to 1 airy unit were recorded on a Zeiss LSM510 META confocal laser scanning microscope and merged to one single image using Fiji imaging software. Apoptosis Assay Apoptosis of cells was measured using a biosensor purchase SB-590885 developed by PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/19657107 Kim et al.. Briefly, cells were seeded in a BD Falcon 96-well imaging plate and incubated overnight. On the day of assay, cells were washed once with control or FK866 containing medium before adding 100 ml of fresh control or FK866 medium containing 8 ng/ml pSIVA or non-labeled control. The plate was immediately imaged for 24 hours, continuously, on a BD Pathway high-content spinning disc confocal microscope, using a 20x objective and 262 montage capture. Three wells were imaged per condition and the amount 
of apoptosis was determined by analyzing the increase in GFP-signal. For each well the threshold of the whole GFP-image series was adjusted and the total pixel area/frame was determined using Fiji imaging software and plotted against time. Phagocytosis Assay Phagocytic activity was determined as zymosan ingestion capacity essentially as described by Kuiper et al.. Zymosan particles were dissolved in PBS at 10 mg/ml and left to rehydrate for at least one hour. Next, zymosan was sonicated three times for 5 seconds, spun down, resuspended in carbonate buffer, sonicated, and incubated with 1 mg/ml fluorescein isothiocyanate for 1 hour at room temperature, in the dark. After FITC labeling, zymosan was washed three times with carbonate buffer and incubated in 1 M Tris-H