sentences:  NO inhibits tyrosine phosphorylation of the kinases involved in production of the interleukin-2 (IL-2) receptor, the expression of which is fundamental for T cell proliferation.In humans, however, NOS2 activity has been difficult to verify.There are two explanations for the lack of responsiveness in the promoter of human inducible nitric oxide synthetase (iNOS) to NO activation by lipopolysaccharides (LPS) + interferon gamma (IFNγ).