Role of chicken TL1A on inflammatory responses and partial characterization of its receptor

The role of chicken TNF-like ligand 1A (ChTLlA) on inflammation and its receptor candidates was investigated to further understand its function as a proinflammatory cytokine. ChTLlA decreased the viability of CH0-K1 cells transfected with chicken TNFR2 or decoy receptor 3 and bound to TNFR2 and decoy receptor 3. ChTLlA was detected in chicken blood samples taken 4 h after LPS injection. Increased mRNA for inflammatory response-related factors such as IL-1β, IL-6, ChTLlA, IFN-γ, inducible NO synthase, and cyclooxygenase 2 were found in spleen samples following LPS injection. Ceruloplasmin and aj acid glycoprotein (as positive acute phase proteins) were increased in chicken plasma 12 h after ChTLlA injection. The injection of anti-ChTLlA Ab was able to prevent typical increases in plasma nitrite plus nitrate, ceruloplasmin, and α₁ acid glycoprotein concentrations following LPS injection. These results indicate that ChTLlA is a proinflammatory cytokine in chickens, animals that do not have TNF-a and lymphotoxin a orthologous genes, and that its proinflammatory action is, at least in part, expressed through binding to TNFR2.