Figure 6.

Proliferation responses to PPD-treated day 14 γδT cells. Day 14 γδT cells from healthy individuals were treated overnight with PPD at concentrations as indicated, washed, and mixed with freshly isolated, CFSE-labeled PBMC from donor-matched blood samples at a γδT cell to PBMC ratio of 1:5. At day 6 (and days 8 and 10; not shown), proliferating CD4⁺ and CD8⁺ αβT cells were identified by flow cytometry in the Vγ9⁻ CD3⁺ T cell gate as activated (CD25⁺) CFSE^low cells. Control cultures (no γδT) contained CFSE-labeled PBMC but not γδT cells. One representative of four independent experiments is shown.