In vitro effect of (3-amino-1-hydroxypropylidene)-1,1-bisphosphonic acid (APD) on the function of mononuclear phagocytes in lymphocyte proliferation.

The effect of (3-amino-1-hydroxypropylidene)-1,1-bisphosphonic acid (APD) on pokeweed mitogen-stimulated and non-stimulated cultures of peripheral blood mononuclear cells was studied in vitro. It is shown that APD can inhibit partially lymphocyte proliferation when added to a suspension of mononuclear cells before stimulation, but that lymphocyte proliferation can continue when the drug is withdrawn. In contrast; when APD is added to the cell suspension together with the mitogen, lymphocyte proliferation remains low even when the drug is withdrawn. Addition of different concentration of mononuclear phagocytes (MNP) to non-adherent cells, followed by stimulation in the presence of APD, indicates that APD acts on MNP function preferentially and does not affect lymphocyte proliferation.