Figure 4. Expanded cells have properties similar to DN2/DN3 stage thymocytes.

Lin⁻Sca-1⁺c-Kit⁺ cells were prepared by sorting cells recovered from 28 day cultures of Lin⁻ c-Kit^lo IL-7Rα⁺ bone marrow progenitors. This eliminated the small numbers of stromal, T and NK cells present at that time Highly enriched lymphocytes from the long term cultures were then compared to freshly sorted CD3ε⁻ CD4⁻ CD8⁻ NK1.1⁻ Mac-1⁻ CD19⁻ adult thymocytes that were further resolved into DN subsets according to expression patterns of CD44 and CD25. RT-PCR analyses were performed to detect transcripts that vary in a stage dependent fashion (22). The plots depict values obtained with freshly isolated thymocytes and the stars show results obtained with cultured cells.