The number of IFNγ-producing CD8 T cells in response to HIV-1–infected CD4 T cells increases substantially in some HIV-1–infected patient samples when IL-2 is added during the stimulation.

Background IFN production in the presence of IL-2 but not infected CD4 T cells was low (< 0.05%) and was subtracted to get the frequency of specific producers. Data are taken from Shankar et al.8