Measurement of proliferative responses of cultured lymphocytes.

Measurement of proliferative responses of human lymphocytes is a fundamental technique for the assessment of their biological responses to various stimuli. Most simply, this involves measurement of the number of cells present in a culture before and after the addition of a stimulating agent. This unit contains several different prototype protocols to induce proliferation in lymphocytes following exposure to mitogens, antigens, allogeneic or autologous cells, or soluble factors. Each of these protocols can be used in conjunction with an accompanying protocol, which contains methods to determine cell proliferation by incorporation of [(3)H]thymidine into DNA by nonradioactive methods, e.g., reduction of tetrazolium salts (MTT or WST-1). These protocols provide an estimate of cell proliferation indirectly by measuring DNA synthesis, and cell metabolic activity in an entire cell population, but no data on individual cells is obtained. A protocol for CFSE labeling allows direct detection of single proliferating cells and facilitates the quantification of cell divisions by flow cytometry according to the respective CFSE-dilution, and following costaining with fluorescent labeled antibodies, the characterization of subpopulations in the cell culture.