Hello Kaled Nather Taha

When cytokines are released, the biologically active amounts of a cytokine can be modulated by soluble ligands which are in the form of nonreceptor cytokine-binding proteins, autoantibodies, soluble specific receptors, and also by proteolytic enzymes. All soluble ligands having cytokine-binding capacity participate in the regulation of cytokine delivery and homeostasis. The net effect of cytokine either inhibition or activation will depend on the properties of the binding protein and the kinetics of binding. The soluble receptors and other soluble ligands increase the concentration of cytokines in body fluids by increasing their stability and decreasing their proteolytic degradation. Upon dissociation from soluble ligands, the biologically active cytokines can reach and activate specific membrane receptors. So binding affinity plays an important role in determining the relevance of soluble ligands in cytokine homeostasis. Finally, cytokine activity can be controlled by transcription-factor inhibitors. A characteristic feature of cytokines is that they generate and act within a network through synergistic and antagonistic interactions. So, the homeostasis between agonists and antagonists probably becomes more important.

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Best.

Malcolm Nobre very thanks to u dr.

you arrangement my scatter info about cytokine hemostasis mech.

There is a great bias in the literature in understanding cytokines only as soluble factors in the blood, because that's what we can most easily measure. Few people even bother to assess what fraction of soluble cytokine is free and active, vs bound by soluble receptors and other binding proteins and inactive or modulated in some way.

That doesn't even scratch the surface of what's going on locally in the tissues. Often, local levels are high enough to match the receptor kD, but serum levels are not. You could view the serum levels as waste cytokine that's on the way out, after it did its job in a locally intelligent manner in the tissues. We measure them when the job is done, and their status no longer particularly matters.