Fig. 2

Intravenous injection of DPG induces an increased reactivity of γδ T cells. The Vγ9Vδ2 T cell expansion was monitored by measuring DNA synthesis after 5-day stimulation (A) or by flow cytometry after 10 days (B). Previous experiments (data not shown) have indicated that among the peripheral blood leukocytes proliferating in the IPP response, the Vγ9Vδ2 T cell subset forms a dominant population, whereas other proliferating leukocytes (which respond by DNA synthesis to Vγ9Vδ2 T cell-produced cytokines) constitute a minority. Cytokine production (C) was monitored by ELISA (TNF-α) or by flow cytometry (IFN-γ) before and 1 month after the injection of DPG in vivo. The production of TNF-α was detectable by the ELISA assay only after the administration of DPG.