T cell-derived interferon-γ is required for host defense to Toxoplasma gondii.

Interferon-γ (IFN-γ) is important for host defense against various intracellular organisms including a protozoan pathogen Toxoplasma gondii. Various immune cells are recently shown to produce IFN-γ in T. gondii infection, however, it remains elusive which cell types are important for anti-T. gondii host defense so far. Here we generate a new IFN-γ reporter "GREVEN" mouse line in which a fusion protein of Venus and NanoLuc to analyze IFN-γ producing cells during T. gondii infection and find that CD4+, CD8+, γδ T cells and natural killer cells express Venus in a time dependent manner. Furthermore, Lck-Cre/Ifngfl/fl mice are highly susceptible to T. gondii infection. Taken together, our results demonstrate that T cell-derived IFN-γ plays an important role in anti-T. gondii host defense.