Table 1.

Reference	McQualter et al.; Stem Cells 2008	Teisanu et al.; Stem Cells 2008	Kim et al.; Cell2005	Summer et al.; AJRCMB 2007
Isolation Optimized For:	--	Bronchiolar Cells	Alveolar Cells	Epithelial Cell Exclusion
Digestive Enzyme(s) / Enrichment Strategies	Collagenase Density gradient centrifugation	PBS/EGTA Elastase DNase	Dispase Collagenase Agarose DNase	Collagenase Dispase
Stem / Progenitor Phenotype	CD45- CD31- Sca-1+ CD34+(a) Thy-1(b)	CD45- CD31- Sca-1low CD34-A plow/hi (d)	CD45- CD31- Sca-1+ CD34+	SP CD45- CD31- Sca-l+(e) (others)(e)
Stem / Progenitor Cell Type	Mesenchymal	Epithelial (Bronchiolar)	Epithelial	Mesenchymal
Primary Culture Media / Conditions	Low Oxygen; 20% serum OR defined serum-free media	ND	10% serum	20% serum (SP); 10% serum (non- SP)
Primary Culture Substrate	Laminin-coated plates	ND	On MEFs	Plastic
In vitro Differentiation Capacity	Cartilage, Bone(c); Fat (bFGF supplement); Fat/ Fibroblastic Cells (ALI culture)	ND	Alveolar and Bronchiolar Lineages (on Matrigel)	Smooth Muscle, Cartilage, Bone, Fat (published differentiation protocols)
In vitro Self-renewal Potential	Yes (clonogenic assays, LD)	ND	Yes (serial passaging, clonogenic assays, LD)	Yes (serial passaging)
Sca-1 In situ Expression	Endothelium, Distal parenchyma	Endothelium, Proximal airway epithelium	Endothelium, Ciliated Cells, BASCs	Endothelium (Summer et al., 2003)

^aanalysis only; not used to sort populations for in vitro assays

^bheterogeneous expression; Thy-1^hi and Thy-1^low fractions show distinct potential in culture assays

^cdata not published

^dAF = autofluorescence in the AlexaFluor 647 and PE channels; low = stem cells, high = facultative transit-amplifying cells

^eexpression determined after long-term culturing

Abbreviations: ALI = air-liquid interface; LD = limiting dilution; ND = not determined; MEFs = mouse embryonic fibroblasts