Coadministration of IL-2 increases the frequency of IFN-γ-producing T cells. Mice were injected subcutaneously with 2 × 105 Renca s.c. into the upper foot to enable isolation of popliteal lymph nodes as distinct tumor-draining nodes. Some groups received Tri-mAb i.p. on days 10 and 13, and/or IL-2 at the dose of 105 IU i.p. on days 10, 11 and 13. Control mice received MAC4 (rat IgG2a) plus UC8-1B9 (hamster IgG) i.p. On day 14, mice were culled and popliteal lymph node cells stimulated on anti-CD3 antibody-coated plates with GolgiStop overnight. Each lymph node analyzed individually. Cells were harvested the next day and stained and assessed by flow cytometry for intracellular IFNγ. Standard error of the mean is shown for 6 mice per group.