HUMAN MONOCYTE CYTOTOXICITY TO TUMOR-CELLS .1. ANTIBODY-DEPENDENT CYTOTOXICITY

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  • 1 January 1978
    • journal article
    • research article
    • Vol. 121  (2) , 573-578
Abstract
Recent investigations examining mononuclear cell antibody-dependent cell-mediated cytotoxicity against tumor cell lines suggest that K [antibody dependent cytotoxic] lymphocytes and not monocytes are active in this cytotoxic reaction. It was found, however, that in an allogeneic assay system, human monocyte monolayers and lymphocytes mediate substantial lysis of 51Cr-labeled antibody-coated CEM [human] lymphoblast tumor cells. This cytotoxicity is temperature-dependent and rapid, with most 51Cr release occurring in the first 4 h of co-incubation. Interaction between target cell-bound antibody and the monocyte Fc receptor is necessary as demonstrated by the marked fall in antibody-dependent cell-mediated cytotoxicity (ADCC) produced by staphylococcal protein A, high concentrations of nonspecific immunoglobulin and dilution of the target cell antiserum. Morphologic and functional characteristics of the monocyte-monolayer preparations establish their relative purity (> 95%) and indicate that monocytes and not contaminating lymphocytes are responsible for tumor cell lysis. Preincubation of monocyte and lymphocyte preparations with latex particles or low concentrations of immunoglobulin distinguished monocyte from lymphocyte ADCC. Thus, normal human monocytes have the capacity to carry out antibody-dependent cytotoxicity against nucleated malignant target cells.