The haemolytic plaque reduction technique to measure cytotoxicity with hybridoma cells as a target

The use of hybridoma cells as targets to measure cell-mediated cytotoxicity has been established. The ability of target hybridoma cells to form haemolytic plaques has been used as an indicator of target viability and therefore, cytotoxicity has been detected by plaque reduction (PR). Allogeneic responses, spontaneous cytotoxic responses and anti-hapten responses have been measured by the PR assay. Compared with the standard [51Cr]chromate release assay, small numbers of target cells (400 or less) can be used in the PR assay and this results in a greatly enhanced sensitivity in detecting small amounts of cytotoxicity. The ability to construct a range of hybridoma targets with the appropriate cell surface determinants presents a new approach, of general applicability, to the sensitive detection of cytotoxic lymphocytes.