Specifically, studies using mouse models have shown that during viral, bacterial, and parasitic infections, neutrophils may acquire suppressive phenotypes characterized by inhibition of T lymphocyte proliferation and activity through arginase-1, inducible nitric oxide synthase (iNOS), and reactive oxygen species (ROS) production and induction of T cell anergy through PD-L1/PD-1-mediated interaction [22–32]. Here, NOS2 is linked to parasitic infectious disease.