Quantitation of antibody-complement mediated lysis of tumor cells

An assay for quantitating antibody-complement mediated killing based on the release of 125I from 125IUdR labelled target cell is described. The temporal delay between antibody--complement damage and the release of nuclear material was shortened by treatment of the cells with a combination of trypsin and DNase. This treatment increased the rate of release of the labelled nuclear material from damaged cells without causing labelled nuclear material to be released from undamaged cells. The low level of spontaneous release of 125I from the target cells allows this assay to be used for experiments carried out over long time periods or in experiments involving extensive manipulations of the cells.