U937-CD80 cells may induce a Th2 cytokine profile. T cells were cocultured with irradiated U937-M3P, U937-CD80, or third-party DCs in a 5-day MLLR and cytokine ELISAs were performed on the resultant supernatant. DCs produced a Th1 cytokine pattern as anticipated (high levels of γ-IFN and IL-2). Of 5 experiments using different responders, only 1 demonstrated detectable cytokine production. This was more of a Th2 cytokine pattern (IL-4 and IL-10 were detected and IL-2 and γ-IFN were much lower than induced by the DCs). There was no detectable cytokine production (IL-2, IL-4, IL-10, or γ-IFN) from 5-day irradiated U937 cells alone.