Antibody-dependent, cell-mediated cytolysis (ADCC) with antibody-coated effectors: rat and human effectors versus tumor targets.

We have previously described techniques that cause antibody molecules to remain bound to P388D1 cells for at least 18 hr, and enable these cells to lyse hapten-coated erythrocytes not sensitized with antibody. These methods collectively are called "franking." In this study, we have determined that these methods are applicable to other systems. We franked rat splenocytes and human peripheral blood leukocytes with rabbit anti-TNP antibody, and showed that they were capable of lysing TNP-tumor and erythrocyte targets (not coated with antibody) in a hapten-specific, antibody-dependent fashion. Both the mononuclear and the polymorphonuclear (PMN) leukocyte fractions of the human cells were capable of mediating lysis. Additionally, human leukocytes franked with rabbit antibody were stained with fluorescent goat anti-rabbit IgG Fab, and were analyzed for fluorescence by flow microfluorometry. Nearly all of the PMN cells and about one-half of the mononuclear cells had IgG on their surfaces after franking. Clearly, not all cells can be franked, but those that can retain significant numbers of antibody molecules (approximately 5 X 10(4), in the case of PMN cells) on their surfaces.