5'nucleotidase activity in mitogen-stimulated adult and cord blood lymphocyte cultures.

Ecto 5'Nucleotidase (5'N) activity was determined in adult and cord blood lymphocytes before and after stimulation by phytohemagglutin (PHA) and pokeweed mitogen (PWM). After 7 days of culture, the mean 5'N level +/- S.E. in unstimulated adult cells was 15.9 +/- 3.21 nm/h/10(6) cells. Cells stimulated by PHA and PWM for 7 days had 5'N levels of 44.65 +/- 6.69 nm/h/10(6) cells and 33.24 +/- 7.67 nm/h/10(6) cells, respectively. Unstimulated cord blood cells cultured for 7 days had a mean 5'N level of 3.22 +/- 0.94 nm/h/10(6) cells whereas the level in PHA-stimulated cultures was 39.50 +/- 10.52 nm/h/10(6) cells and in PWM stimulated cultures 46.01 +/- 8.93 nm/h/10(6) cells. T-cell enriched and T-cell depleted subpopulations stimulated with mitogen generally did not show as great a degree of enhancement of 5'N activity as did unfractionated cells. This study indicates that 5'N activity is enhanced in cells that have been activated by mitogen stimulation. Although unstimulated cord blood cells have lower levels of 5'N activity than adult cells they have the capability upon stimulation to express levels equal to those found in adults.