A novel culture system for induction of T cell development: modification of fetal thymus organ culture.

We have previously found that the development of T cells predominantly of the T cell receptor alpha beta T cell lineage, which is comparable to that in the organ culture (OC) of fetal thymus at the air-medium border (AMB), could be induced in submersion OC of murine fetal thymus if the cultivation was performed in an environment containing O2 at 60-80%. This culture method is named high oxygen submersion (HOS)-OC. In the present work, we established a culture system where T cell development can be induced from thymic as well as fetal liver progenitors by cocultivating them in a 96-well U-bottom plate with a deoxyguanosine (dGuo)-treated fetal thymus lobe under HOS conditions. Differentiation and growth of T cells in this culture system were comparable to those seen in the previously devised micro i.t. system, where progenitor cells were injected with a microinjector into dGuo-treated lobes and were cultured under AMB conditions. A similar level of T cell development was induced by cocultivating such progenitors with small fragments of thymus lobes under HOS conditions. Moreover, it was possible to induce T cell development by culturing fetal thymus cells with thymic stromal cells prepared by treating dGuo-treated lobes with trypsin plus EDTA in a V-bottom plate under HOS conditions.