Establishment of human double-positive thymocyte clones

Human thymocytes were sorted according to the expression of CD4 and CD8 molecules and clones representing the four subpopulations (DP, DN, and single CD4 or CD8 positive) were established. DP clones can be maintained for long periods in tissue culture and give rise to a variable percentage of SP variants. These variants, when isolated and further expanded, do not revert to a DP phenotype. DP clones express a functional TCR-CD3 complex, suggesting that this molecule can interact with the thymic microenvironment during T cell differentiation.