thymocyte quantity double-negative T cell quantity DN3 thymocyte quantity DN3 cell number csmith VT:0010134 DN3 alpha-beta immature T-lymphocyte number DN3 alpha-beta immature T-cell number TN3 thymocyte number Trait.ontology DN3 immature T cell number DN3 alpha-beta immature T lymphocyte number 2010-04-14T02:59:48Z TN3 cell number The proportion or number of thymocytes that have the cell surface marker phenotype CD4-negative, CD8-negative, CD44-negative, and CD25-positive and expressing the T cell receptor beta-chain in complex with the pre-T cell receptor alpha chain.