Figure 4From: Macrophages and cytokines in the early defence against herpes simplex virusRegulation of iNOS induction at the cellular level. Cytokines controlling the iNOS induction in macrophages (Mφ) during early HSV infection. IFN-γ, produced mainly by NK cells, stimulates iNOS production. This IFN-γ-induced production of iNOS can be inhibited by IL-4. Upon HSV infection of macrophages they produce TNF which synergizes with the IFN-γ-induced pathways and inhibits the inhibitory signals of IL-4. Thus, the virus overrules the restrictive signals and opens up for an otherwise closed pathway. Stimulatory pathways are indicated by green arrows (→), and inhibitory pathways are drawn in red.Back to article page