UC Merced

We investigated the phenotypic and molecular characteristics of a rare human adult bone marrow (ABM) CD34+CD38-/loCD7+CD10- population that comprise 0.04% of the total bone marrow mononuclear cells in search of a human committed T cell progenitor (hCTP). Using multi-color flow cytometry, we investigated our putative hCTP for its cell surface phenotype and sorted cells for molecular analysis. We observed that our putative hCTP population expresses low levels of T cell lineage associated surface markers CD1a and CD5; the chemokine receptors implicated with progenitor migration to the thymus CCR7, CCR9, CXCR6; and lymphoid associated surface markers CD127, CD45RA, and CD24. Using the comparative CT quantitative PCR method, we established a gene expression profile of our putative hCTP. Molecular analysis reveals that the putative hCTP population lacks expression of T cell lineage genes (Gata-3, CD7, CD3) and the lymphoid lineage associated gene Rag-1. However, expression of PU.1 and Id2 is present in this population, similar to early thymocytes. Based on our results, we conclude that this population resembles the human early thymic progenitor, and is capable of seeding the thymus.