Figure 7.

Vδ1⁺ T cells differentiate into αβT cells. RAG and TdT expression in panVδ1⁺ cultures, native and over time in different inflammatory culture conditions; correlation of TCR DP cells with CD4⁺Vδ1⁺ and residual αβT-cell numbers in initial panVδ1⁺ T-cell pools. (A) panVδ1⁺ T cells cultivated in the presence of IL-7, PHA, IL-2, and irradiated allogeneic feeder cells gave rise to a cell fraction that co-expressed Vδ1 and TCR-αβ after 3 weeks, before differentiating into TCR-αβ⁺ T cells. Series of dot plots are representative of 12 independent experiments. (B) Number of Vδ1⁺/TCR-αβ⁺ cells varied between individuals (mean: 0.926%/Vδ1⁺; range 0.1–3%) (right) as did the number of produced αβT cells (mean: 1.82%/Vδ1⁺; range 0.2–6.0%) (left); Vδ1⁺/TCR-αβ⁺ double-positive cells in week 3 of culture corresponded with the number of CD4⁺ Vδ1⁺ T cells in initial Vδ1⁺ T-cell pool (left). There was no correlation between residual TCR-αβ⁺ T cells after Vδ1⁺ cell separation and set-up of initial Vδ1⁺ T-cell culture and the number of Vδ1⁺/TCR-αβ⁺ double-positive T cells after 3 weeks of culture (right). Each dot represents one independent experiment. (C) After initial depression, RAG-1 and TdT quantities subtly increased in Vδ1⁺ cell cultures and were detectable simultaneously with the appearance of Vδ1⁺/TCR-αβ⁺ coexpressing cells. m, Mild inflammation (IL-7, PHA, IL-2, and irradiated allogeneic feeder cells); o, overt inflammation (exposure to strong inflammatory stimuli in week 3, conditions described in the Section “Materials and Methods”); week 0, freshly isolated, native Vδ1⁺ cells were analyzed.