Failure of hydrocortisone to inhibit blastogenesis by pokeweed mitogen in human leucocyte cultures.

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  • 1 July 1972
    • journal article
    • Vol. 11  (3) , 393-403
Abstract
Hydrocortisone was added to cultures of human peripheral blood leucocytes 30 min before the addition of phytohaemagglutinin (PHA) or pokeweed mitogen (PWM). A concentration of 10 μg/ml of hydrocortisone inhibited a major part of the blastogenic response to PHA at 3 days of incubation and prevented a decline in the number of macrophages. A portion of corticosteroid-resistant PHA-stimulated blasts was observed in all experiments. Hydrocortisone (10 μg/ml) caused a slight decrease in the mitogenic response to PWM at 2 and 3 days of incubation, but at 5 days the proportion of blasts equalled or exceeded that seen in cultures with PWM alone. Hydrocortisone did not prevent the virtual disappearance of macrophages from cultures incubated with PWM or with a combination of PHA and PWM. The effect of hormone on both lymphocytes and macrophages indicated that the principal action of PWM was on a subpopulation of lymphocytes not responsive to PHA. In addition a small number of corticosteroid-sensitive cells was transformed by PWM early in incubation. Results indicated that the prior addition of corticosteroids to leucocyte cultures was useful in determining the response of segments of the circulating lymphocyte population to different mitogenic stimulants.