Isolation of definitive zone and chromaffin cells based upon expression of CD56 (neural cell adhesion molecule) in the human fetal adrenal gland.

The cortex of the human midgestation adrenals comprises a thin layer of cells, the definitive zone (DZ) that surrounds the larger, inner fetal zone (FZ). CD56 expression was observed by immunohistochemistry on DZ cells and isolated groups of cells within the FZ. CD56 mRNA expression also was detected among DZ cells but not selected sections of FZ cells isolated by laser capture microdissection. Flow cytometric analysis of dispersed adrenal cells indicated CD56 expression on a subset of adrenal cells lacking expression of hematopoietic (CD45(+) and CD235a(+)) and endothelial (CD31(+)) cell markers. The CD56(+)CD31(-)CD45(-)CD235a(-) cells were isolated by discontinuous-gradient centrifugation and fluorescence-activated cell sorting. The purified cells were enriched for DZ cells based on expression of mRNA for metallopanstimulin-1, nephroblastoma overexpressed gene, and 3-beta-hydroxysteroid dehydrogenase. P450c17 mRNA expression also was detected among a subset of CD56(+) cells consistent with expression of low levels of this protein in some DZ cells. The presence of a subpopulation of chromaffin cells among the CD56(+) population also was shown by the expression of chromogranin A mRNA. These findings indicate that CD56 expression can be used to isolate DZ and chromaffin cells to further study their functional and developmental properties.