Divided we stand: Tracking cell proliferation with carboxyfluorescein diacetate succinimidyl ester

Most techniques for assessing cell division can either detect limited numbe rs of cell divisions (bromodeoxyuridine incorporation) or only quantify ove rall proliferation (tritiated thymidine incorporation). In the majority of cases, viable cells of known division history cannot subsequently be obtain ed for functional studies. The cells of the immune system undergo marked pr oliferation and differentiation during the course of an immune response. Th e relative lack of an organized structure of the lymphohaemopoietic system, in contrast with other organ systems, makes lineage interrelationships dif ficult to study. Coupled with the remarkable degree of mobility engendered by recirculation, the differentiation occurring along with cell division in the immune system has not been readily accessible for investigation. The p resent article reviews the development of a cell division analysis procedur e based on the quantitative serial halving of the membrane permeant, stably incorporating fluorescent dye carboxyfluorescein diacetate succinimidyl es ter (CFSE or CFDA, SE). The technique can be used both in vitro and in vivo , allowing eight to 10 successive divisions to be resolved by flow cytometr y. Furthermore, viable cells from defined generation numbers can be sorted by flow cytometry for functional analysis.