Induction of suppressor cells after activation of human peripheral blood mononuclear cells with sodium periodate.

Pretreatment of normal human peripheral blood mononuclear cells (MN) with sodium periodate (NaIO4) resulted in the induction of suppressor cells. The mitogenic response of fresh allogeneic and autologous cells to phytohaemagglutinin (PHA), Concanavalin A (Con A), pokeweed mitogen (PWM), various antigens and in mixed lymphocyte culture was suppressed when NaIO4 pretreated cells were present. PWM-induced plaque-forming-cell responses were also suppressed by NaIO4-pretreated cells. Treatment of cells with mitomycin C before the NaIO4 treatment abolished the suppressive activity. A ratio of 1 : combination that resulted in the strongest suppression. Supernatants from NaIO4-pretreated cell cultures were not inhibitory.