CD4 and breast carcinoma: We then evaluated the levels extracellular adenosine from the supernatants of different breast cancer-infiltrating immune cells (CD73+Vδ1 T, CD73-Vδ1 T and CD4+CD25+ T cells) co-cultured with CD3+ T cells and found that adenosine was highest in the presence of CD73+Vδ1 T cells compared with that in the presence of the other cell types (Fig. 3g).