TNF alpha and IFN gamma, granulomas.

[anbuitachi]

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In first aid it says TNF alpha inhibitors can activate latent TB because it prevents activation of macrophages. In most questions i've seen, IFN-gamma was related to activating macrophages and making granulomas..

Does anyone know any immunology behind the two factors that relate to this? Since w/o TNF, there's still IFN-gamma to activate the macrophages? Not sure why TNF creates this effect

 

[TrueAntagonist]

1) TNFa MAINTAINS granulomas (not sure how, but don't think it matters much).
Thus, anti-TNFa drugs like infliximab, etanercept causes 'dissolution' of the granuloma and the cordoned off mycobacterium is let loose --> TB

2) IFNg does, indeed, activate macrophages and gives them the signal to kill intracellular Mycobacterium.

Both components are needed to effectively deal with mycobacterium.

Please feel free to correct me if I'm wrong.

 

[anbuitachi]

Oh, thanks, that makes sense

 

[loveoforganic2]

My understanding is macrophage infected => macrophage release of IL-12 => Th differentiation into Th1 cells => Th1 release of IFN gamma => macrophage activation => activated macrophage release of TNF-alpha => monocyte recruitment and differentiation into epithelioid histiocytes (granuloma)

 

[TrueAntagonist]

My understanding is macrophage infected => macrophage release of IL-12 => Th differentiation into Th1 cells => Th1 release of IFN gamma => macrophage activation => activated macrophage release of TNF-alpha => monocyte recruitment and differentiation into epithelioid histiocytes (granuloma)

This. End result being: TNFa from IFNg-activated macrophages maintains granulomas.