Cells of the J774 macrophage cell line are primed for antibody-dependent cell-mediated cytotoxicity following exposure to gamma-irradiation.
Activation of macrophages (M phi) for host defense against tumor cells follows a sequence of priming events followed by an initiating stimulus that results in production and release of cytotoxic molecules that mediate target cell killing. We have developed a model to study specific macrophage cytotoxicity in vitro utilizing a cultured murine M phi cell line, J774. Specific cytotoxicity of cultured human gastrointestinal tumor cells is achieved in the presence of murine IgG2a monoclonal antibody (mAb) 17-1-A. The ability of these cells to mediate antibody-dependent cell-mediated cytotoxicity (ADCC) is greatly enhanced following gamma-irradiation. ADCC can be demonstrated at mAb 17-1-A concentrations greater than or equal to 1 microgram/ml and effector/target cell ratios greater than or equal to 2. Exposure to doses greater than or equal to 10 Gy of gamma-irradiation increases ADCC threefold. Varying the duration from J774 M phi exposure to gamma-irradiation until addition of antibody-coated target cells showed that the primed state for ADCC is stable for at least 8 days but approximately 24 hr is required for complete development of the primed state. mAb-dependent target cell death begins 8 hr after addition of mAb and labeled target cells to primed effector cells and is complete by 24 hr. Incubation of unirradiated J774 M phi effector cells with recombinant murine interferon-gamma (rmIFN-gamma) also results in enhanced ADCC, but the extent of target cell killing achieved is less than that following priming by gamma-irradiation. Concomitant priming of gamma-irradiated J774 M phi with rmIFN-gamma increases the extent of ADCC. Further study of irradiated J774 cells may elucidate the molecular pathways utilized by M phi for achieving and maintaining the primed state for ADCC. Irradiated J774 cells will also provide a homogenous, stably primed cell type in which to examine the mechanism(s) of cytotoxicity employed by tumoricidal M phi.
Duerst
R
R
Department of Pediatrics, University of Rochester Medical Center, New York 14642.
Werberig
K
K
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000920:Antibody-Dependent Cell Cytotoxicity / Q000187:drug effects / Q000528:radiation effects; D000943:Antigens, Differentiation / Q000276:immunology; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D005720:Gamma Rays; D007116:Immunization, Passive; D066298:In Vitro Techniques; D007371:Interferon-gamma / Q000494:pharmacology; D008264:Macrophages / Q000166:cytology / Q000276:immunology* / Q000528:radiation effects; D051379:Mice; D011961:Receptors, Fc / Q000276:immunology; D017452:Receptors, IgG; D011994:Recombinant Proteins
D000911:Antibodies, Monoclonal; D000943:Antigens, Differentiation; D011961:Receptors, Fc; D017452:Receptors, IgG; D011994:Recombinant Proteins; D007371:Interferon-gamma