p55- Tnfrsf1<atm1Imx> TNFR<-> TNFR1- Null/knockout http://identifiers.org/mgd/MGI:1857468 MGI:1857468 Tnfrsf1a<tm1Imx> targeted mutation 1, Immunex Research and Development Corporation p55 KO TNFRI- Preschon Tnfrsf1a<-> TNF-alpha-R1