Table 1_Upregulation of CD90 correlates with T lineage commitment at the DN2a stage of T cell development.xlsx

This revealed heterogeneity within DN2a thymocytes. We identified two subpopulations, which we termed DN2a-1 and DN2a-2, based on differences in CD34, CD90, and Bcl11b expression. DN2a-1 thymocytes co-expressed multipotency and T-lineage-associated markers, whereas DN2a-2 cells mainly displayed a transcriptional profile consistent with T-lineage commitment.

Functional assays demonstrated that DN2a-1 thymocytes were more developmentally advanced than ETPs but remained multipotent, whereas DN2a-2 thymocytes were more mature and largely restricted to the T lineage. Furthermore, in vivo clonal lineage tracing indicated that these subsets were on a developmental continuum. Together, these findings reveal that the heterogeneous DN2a stage can be resolved further by CD90 expression into pre- and post-T lineage-restricted subsets.</p>