Measurement of DNA synthesis in leucocyte microcultures

A microculture technique is described in which human peripheral blood leucocytes undergo DNA synthesis in response to specific and non-specific blastogenic factors. A sensitive Millipore filter assay technique is shown to be suitable for determining the incorporation of radioactive thymidine into the DNA of the stimulated cells in these microcultures. With these methods it is possible to measure the DNA synthesis in a 50-mul culture containing an innoculum of only 10(5) leucocytes. This small culture volume, with its low number of leucocytes, therefore makes it possible to perform experiments when either the available leucocytes or blastogenic factors are in limited supply.