FIG. 3.
TNF-α and IFN-γ production in cocultures of B. suis-infected macrophages and autologous NK cells. Infected macrophages (8 × 105/well) were cultured in 1 ml of culture medium in the presence of NK cells for different periods of time (ratio of NK cells to B. suis-infected cells = 1). TNF-α and IFN-γ secreted in cell culture supernatants were measured in triplicates as described in Materials and Methods, and means of four different experiments are shown. First, we confirmed that B. suis-infected macrophages did not secrete TNF-α or IFN-γ (•). Addition of NK cells to the infected macrophages resulted in strong production of TNF-α (▾) and IFN-γ (▿). When noninfected macrophages were mixed with NK cells, only a marginal production of TNF-α (▪) or IFN-γ (□) was observed. Error bars, SEMs for four different experiments.