Inhibitory effects of AcSDKP on the mixed lymphocyte reaction (MLR). Part II. Human whole blood cells.

AcSDKP is a physiological negative regulator of hematopoietic stem cell proliferation. To investigate the applicability of AcSDKP in the prevention of graft-versus-host disease, this tetrapeptide was tested in mice and showed an inhibitory effect on the mixed lymphocyte reaction (MLR). In this paper we report MLR using human whole blood cells. The maximum inhibitory effect (50%) was obtained at 2.5 ng/ml AcSDKP. All experiments showed a constant dose response. Experiments are now being conducted to elucidate the mechanism of this inhibition.