Effect of hydrocortisone on the in vitro human antibody response: interaction with monocytes and prostaglandins

The specific plaque-forming cell response induced by trinitrophenyl polyacrylamide beads in cultures of nonadherent human peripheral blood mononuclear cells (PBM) is resistant to the inhibitory effect of hydrocortisone (HC). Previous results showed that low concentrations (up to 10(-7 M) of HC inhibit the same response in cultures of unfractionated human PBM. It is shown that the addition of 5-10% monocytes to nonadherent PBM renders their response HC-sensitive. One mechanism of the interaction between HC and monocytes is the potentiation of prostaglandin E2-mediated suppression by HC, which can be demonstrated in vitro and after in vivo administration of HC. However, interaction with a non-prostaglandin-mediated suppression by monocytes should be involved, particularly with high (10(-6) M) concentrations of HC.