TNF-alpha indirectly has an effect over infiltration because promote endothelial cells activation and the expression of adhesion molecules by this cells.

IL-6 and TNF-alpha both are proinflammatory cytokines but TNF have more effects than IL-6. TNF act in liver, endothelial cells, hypothalamus , muscle, fat catabolism.

IL-6 is also a "myokine," a cytokine produced from muscle, and is elevated in response to muscle contraction. It is significantly elevated with exercise, and precedes the appearance of other cytokines in the circulation.

During exercise, it is thought to act in a hormone-like manner to mobilize extracellular substrates and/or augment substrate delivery (Petersen, J Appl Physiol 2005). Additionally, osteoblasts secrete IL-6 to stimulate osteoclast formation. Smooth muscle cells in the tunica media of many blood vessels also produce IL-6 as a pro-inflammatory cytokine.

IL-6's role as an anti-inflammatory cytokine is mediated through its inhibitory effects on TNF-alpha and IL-1, and activation of IL-1ra and IL-10.

Tnf-α release in the context of infection or stress has been shown to inhibit IL-6 signaling, whilst in models of rheumatoid arthritis persistent inflammation is found to mediate IL-6 trans activation via TNF-α 'hijacking' the gp130 receptor system. IL-6 is central to the mounting of the acute phase response at the level of the liver and has indeed been shown by Petersen et al to promote nutrient delivery to the muscle during exercise. The antiinflammatory effects can also be directly attributed to its ability to activate SOCS3 via the Jak-Stat pathway, much like IL-10. Importantly, under baseline conditions Il-6 has been shown, in various expression systems and models, to induce increases in pAMPK and pPKB, as well as its 'native' STAT3 and ERK1/2

Thank you very much for both of your answers. I've heard that IL-6 can suppress TNF-alpha as well, especially in macrophage infiltration. I've been trying to look into that pathway in greater details. I'd be very grateful if I could hear more details about it. Many thanks for your kind help and time. Regards, K H

TNF-alpha indirectly has an effect over infiltration because promote endothelial cells activation and the expression of adhesion molecules by this cells

Dear Khaing Htun

IL-6 is a multifunctional cytokine. It is a good "actress", having several roles. IL-6 plays in different theater performances: Myokine, Pro-inflammatory cytokine, Stimulant in osteoclast formation...

IL-6 is involved in multiple epithelial tumors. My special topic is multiple myeloma. I found that IL-6 leads to enhanced proliferation of multiple myeloma cells. IL-6 increases the TNF-alpha production markedly in these cells.

with best

Eva

Thank you very much (Dr Wael & Dr Eva) for your kind help and time. Much appreciated. Regards, K H

I agree with Dr. Wael, but I have an experience with both cytokines.

TNF-a plays a pivotal role in immune transition from innate to adaptive immunity.

TNF-a can promote endothelial cells activation, the expression of adhesion molecules, activation of antigen presentation and enhancing other proinflammatry cytokines.

I can provide with a lot of papers if you want.