This transgene contains the tetracycline-responsive P-tight promoter (from the plasmid pTRE-Tight, BD Biosciences Clontech), which comprises a modified Tet-responsive element containing seven direct repeats of a 36-bp sequence including the 19-bp tet operator sequence followed by a minimal cytomegalovirus (CMV) promoter, driving expression of a human tumor necrosis factor alpha cDNA whose 3' untranslated region (3'-UTR) has been replaced by the SV40 polyadenylation signal. This transgenic line was estimated by Southern blot analysis to carry 5 tandem copies of the transgene. No human TNFalpha is detected by enzyme-linked immunosorbent assay (ELISA) in sera of doxycycline-treated or untreated mice bearing this transgene alone. (J:236003)