Figure 4.

Daudi cells fail to induce γδ T-cell expansion in the absence of CD4⁺ T cells.3×10⁵ irradiated Daudi cells were cocultured with 10⁶ responder lymphocytes for 8 days, harvested, stained, and analysed by flow cytometry. Responder cell populations were total PBMC (panels 1,2,3), CD4-depleted PBMC (panels 4,5,6), and CD8-depleted PBMC (panels 7,8,9). Panels 1, 4, and 7 show 2-color FACS profiles of unstimulated responder lymphocytes stained for CD4 (x-axis) and CD8 ( y-axis). Percentages of CD4⁺ and CD8⁺ T cells are shown in the lower right and upper left corners, respectively. Staining for γδ T cells is shown in panels 2, 5, and 8 (unstimulated lymphocytes) and 3, 6, and 9 (Daudi-stimulated lymphocytes). The percentage of γδ TCR⁺ T cells is indicated in each panel. Irradiated Daudi cells failed to induce γδ T-cell expansion in PBMC populations depleted of CD4⁺ T cells (panel 6). γδ T cell expansion occurred normally in CD8⁺ lymphocyte-depleted responder populations (panel 9). There was no significant staining by isotype-matched control antibodies (not shown). Data shown are representative of one of three experiments.