In vitro analysis of interferon gamma (IFN-gamma) and interleukin-12 (IL-12) production and their effects in ileal Crohn's disease.
Crohn's disease is an inflammatory disease of the gut in which tumour necrosis factor (TNF) and T helper 1 (Th1) cytokines (interleukin (IL)-12, interferon (IFN)-gamma) are thought to play a major role. After the successes obtained with neutralisation of TNF, interest is now growing for therapy aiming at neutralisation of Th1-associated cytokines. Since cytokines are linked in a delicate network, in vitro cultures of ileal lamina propria mononuclear cells (LPMC) were set up for evaluation of a) IFN-gamma and IL-12 production, b) effects of rhIFN-gamma and rhIL-12 and c) effects of anti-IFN-gamma and anti-IL-12 on pro-inflammatory cytokines and IL-10 production. LPMC were isolated from surgical specimens of a total of 27 Crohn's disease and 17 caecum carcinoma (control) patients. Cells were stimulated with CD40L (which triggers myeloid CD40-expressing cells) or anti-CD3 +CD80 (which triggers T cells). LPMC from involved ileal, Crohn's disease produced, in both non-stimulated and stimulated conditions, more IFN-gamma and IL-12p70 than LPMC from non-involved tissue or from control patients. rhIFN-gamma significantly enhanced TNF production in both controls and in ileal Crohn's disease patients, while rhIL-12 enhanced IFN-gamma but not TNF production. LPMC from involved tissue were more sensitive to IL-12 than control LPMC. LP-T cell-dependent activation of monocytes was then studied by co-culture of anti-CD3/CD80-stimulated LPMC with fresh monocytes, which resulted in high IL-12, IFN-gamma, TNF and IL-10 production. The data show that neutralisation of either IL-12 or IFN-gamma with mAb in these cultures also affects secretion of the reciprocal cytokine and (in the case of anti-IL-12) also that of the anti-inflammatory cytokine IL-10. However, no effect of anti-IL-12 or anti-IFN-gamma on production of TNF, a cytokine with an important pathogenic role in Crohn's disease, could be found. Therapies aiming at neutralisation of IFN-gamma or IL-12 are therefore unlikely to replace anti-TNF, but they might provide an additive or synergistic effect.
Colpaert
Stefaan
S
Laboratory of Experimental Immunology, University Hospital Gasthuisberg and Catholic University of Leuven, Belgium. Stefaan.Colpaert@med.kuleuven.ac.be
Vastraelen
Kathleen
K
Liu
Zhanju
Z
Maerten
Philippe
P
Shen
Chong
C
Penninckx
Freddy
F
Geboes
Karel
K
Rutgeerts
Paul
P
Ceuppens
Jan L
JL
D016022:Case-Control Studies; D003424:Crohn Disease / Q000188:drug therapy / Q000276:immunology*; D006801:Humans; D007082:Ileum / Q000276:immunology; D066298:In Vitro Techniques; D007371:Interferon-gamma / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000494:pharmacology; D018664:Interleukin-12 / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000494:pharmacology; D011994:Recombinant Proteins / Q000494:pharmacology; D018417:Th1 Cells / Q000276:immunology
D011994:Recombinant Proteins; D018664:Interleukin-12; D007371:Interferon-gamma