To test the possibility of CCSP + cell isolation by flow cytometry from mouse lung, we established a simple method to make single cell suspensions from lung tissues. Using a combination of mincing by scissors and incubation in a high concentration of collagenase (3 mg/ml) for digestion, single cells were obtained within 2 hours from euthanasia. After an overnight recovery in DMEM/10%FBS cell culture media, cells adherent to culture dishes were trypsinized and sorted using a flow cytometry sorter. In FVB mice, about 25% of the lung cells sorted from one whole lung single cell suspension were CCSP + (Figure 1 ). Typical yields of sorted cells per mouse were about ,2.5610 5 of CCSP + cells and ,4610 5 of CCSP 2 cells. Sorted cells were plated into 100 mm cell culture dish for overnight in an incubator prior to further studies. Unattached dead cells were removed with the media.