Characterization of opt_sgp130Fc transgenic mice. (A) Northern blot analysis showing opt_sgp130Fc mRNA expression in different organs of 2 homozygous opt_sgp130Fc transgenic mice. Mice were killed and total RNA from the indicated organs and tissues was prepared. Eight micrograms total RNA were separated and then hybridized with a ³²P-labeled XhoI restriction fragment comprising the opt_sgp130Fc cDNA. (B) sgp130Fc from opt_sgp130Fc transgenic mice could bind to Hyper-IL6. Hyper-IL6 coprecipitates with sgp130Fc that is present in the serum of opt_sgp130Fc transgenic mice. Hyper-IL6 was detected by Western blotting against sIL6R. One homozygous animal of the line opt3 and one WT animal are depicted. (C) Induction of acute-phase response by Hyper-IL6 in opt_sgp130Fc transgenic and WT mice. Northern blot analysis showing the liver expression of serum amyloid A (SAA2) 4 hours after intraperitoneal injection of 500 ng Hyper-IL6 per mice. Five micrograms total liver RNA were seperated and probed with a ³²P-labeled PCR fragment of the mouse SAA2 gene.