USE OF ANTIBODY-COATED LIPOSOMES AS A TARGET-CELL MODEL FOR ANTIBODY-DEPENDENT CELL-MEDIATED CYTOTOXICITY

Abstract

A simple model system was developed for antibody[Ab]-dependent cell-mediated cytotoxicity (ADCC) using Ab-coated synthetic membranes (liposomes) as a target cell model. A synthetic hapten, dinitrophenyl-phosphatidylethanolamine (DNP-PE), was incorporated into fluorophore-quencher-loaded liposomes and the latter were coated with pure anti-DNP Ab. Normal spleen lymphocytes were capable of binding and subsequently lysing these liposomes. This process is dependent upon the presence of an intact (Fc-containing) Ig[immunoglobulin]G molecule and independent of exogenous serum complement. The effector lymphocytes are nylon non-adherent, devoid of Thy-1 antigen and present in nude mice, suggesting an identity with K [Ab-dependent killer] (Fc receptor positive) lymphocytes. Liposomes may be used as a model to study the requirements for the binding and lysis of target cells in this cell-mediated cytotoxic system.