Generation of vIL-6 transgenic mice. (A) Schematic illustration showing the genetic organization of the vIL-6–expression cassette used for the pronuclei injection of fertilized mouse eggs (p167/2-H2-vIL-6-myc-opt). (B) Southern blot of DNA from 2 founder vIL-6 transgenic mice, 12/3 and 14A/8, using a radiolabeled probe to the complete vIL-6 cDNA. Arrow indicates expected size. (C) Determination of vIL-6 serum concentrations of transgenic founder mice by ELISA. (D) RT-PCR analysis of vIL-6 and β-actin (loading control) expression in various tissues from 2 independent vIL-6 transgenic mouse strains fully backcrossed onto the C57BL/6 genetic background. PP indicates Peyer patches; and BM, bone marrow.