Activation of monocyte-mediated tumoricidal activity in patients with acquired immunodeficiency syndrome.

The purpose of these studies was to determine whether peripheral blood monocytes from acquired immunodeficiency syndrome (AIDS) patients with Kaposi's sarcoma could be activated to lyse human tumor target cells in vitro. Monocytes were isolated and incubated for 24 hours in vitro with either medium (control), a crude mitogen-induced lymphokine preparation (MAF), or endotoxin before the addition of [125I]IUdR-labeled A375 melanoma target cells. Cytolysis was determined 72 hours later.

Lysis of tumor cells by human blood monocytes by a mechanism independent of activation of the oxidative burst.

Tumorilytic human blood monocytes recognize and destroy neoplastic cells by a mechanism that is nonphagocytic and requires cell-to-cell contact. The mechanism of cytolysis subsequent to binding is controversial. Release of reactive oxygen intermediates by activated rodent macrophages has been suggested as an important mechanism for tumor cell lysis in some short-term cytotoxicity assays.

Human monocyte-mediated cytotoxicity against herpes simplex virus-infected cells: activation of cytotoxic monocytes by free and liposome-encapsulated lymphokines.

Human peripheral blood monocytes were incubated with free or liposome-encapsulated human lymphokines containing macrophage-activating factor (MAF) and tested for their effect on herpes simplex virus (HSV)-infected target cells. Activated monocytes lysed allogeneic HSV type 2 (HSV-2)-infected whole human embryo cells and xenogeneic BALB/c mouse embryo cells (10E2) without any significant effect on uninfected cells, as measured by release of 51Cr from target cells after 18 h of cocultivation. Kinetic studies revealed that lysis of virus-infected cells occurred by 10 h following cocultivation with activated monocytes.

Human monocytes activated by immunomodulators in liposomes lyse herpesvirus-infected but not normal cells.

Highly purified peripheral blood monocytes from normal human donors were activated in vitro by incubation with liposomes containing immunomodulators such as recombinant human gamma interferon, human lymphokines, or muramyl dipeptide. The ability of liposomes containing immunomodulators to activate monocytes to a cytotoxic state capable of discriminating between virus-infected and uninfected cells was shown by activated monocytes recognizing and destroying herpes simplex virus type 2-infected cells while leaving uninfected cells unharmed .