Responses of chronic lymphocytic leukemic lymphocytes to increasing concentrations of phytohemagglutinin during short-term culture.

Lymphocytes obtained from CLL patients containing high and low peripheral lymphocyte cell counts were cultured in the absence and presence of increasing concentrations of phytohemagglutinin for periods of up to 2 h. Lymphocytes from patients with low cell counts (less than 50,000/mm3) were stimulated to incorporate 3H-uridine during the 1st h of culture by concentrations of PHA ranging from 1 to 32 microgram/ml. Under identical conditions, lymphocytes from patients with high cell count (greater than 50,000/mm3) were barely affected.

Cortisol resistant RPMI-1788 lymphocytes become sensitive to cortisol subsequent to a 24-h incubation period in medium containing purified human transcortin.

RPMI-1788 lymphocytes (a human cell line) are resistant to cortisol in vitro. Prior incubation for a minimum of 24 h in a medium which contains purified human transcortin at a concentration of 50 micrograms/ml renders these cells sensitive to the inhibitory action of cortisol as regards the synthesis of DNA. Only the transcortin-exposed cells contain a cortisol binding species whose sedimentation behavior in a sucrose gradient is identical to that of transcortin.