An enzyme immunoassay for estimating small numbers of cells

In this report we describe an enzyme immunoassay for determination of cell number in small samples. The assay utilizes a commercially available monoclonal antibody that recognizes double- and single-stranded DNA and works with several different methods of cell fixation. DNA extraction is not required. Confluent, growth-arrested fibroblasts serve as standards. While most readily applicable to anchorage-dependent cells, addition of a centrifugation step allows the method to be applied also to anchorage-independent cells.