Antigen-specific cytokine responses detected to persistent herpes viruses and tetanus toxoid. Following a six hour stimulation, PBMCs were assessed by intracellular cytokine staining for responses to HIV, herpes viruses CMV, EBV, HSV & VZV, and the bacterial antigen tetanus toxoid. Responses were categorized according to the combination of cytokines produced (either IL-2 or IFNγ alone, or both together). Cytokine responses for each antigen are shown with HIV- donors on the left and HIV+ donors on the right. Unpaired 2-tailed t-tests were used to compare responses between HIV+ and HIV- donors.