SELECTIVE RECOGNITION OF THE ACTIVATED FORM OF TRANSCRIPTION FACTOR NF-KAPPA-B BY A MONOCLONAL-ANTIBODY

Transcription factor NF-kappa B is a central regulator of inflammatory , immune and acute phase reactions, It rapidly initiates the transcrip tion of a wide variety of target genes in response to various pathogen ic stimuli. Because NF-kappa B is predominantly controlled at a posttr anscriptional level through association with the inhibitory I kappa B subunits, its activation cannot be monitored directly at a cellular le vel by means of detecting new mRNA or protein synthesis, In this study , we describe a monoclonal antibody, designated alpha-p65MAb, that rec ognizes an epitope which includes the nuclear location signal (NLS) of p65, the DNA binding subunit mainly responsible for the strong gene-i nductory potential of NF-kappa B, alpha-p65MAb recognized human and ro dent p65 only when I kappa B alpha was not bound to p65, Thus, the lgG 3 selectively stained the activated, nuclear form of NF-kappa B in cul tured cells, Unlike I kappa B, the MAb and its Fab fragments did not i nhibit the DNA binding activity of NF-kappa B in mobility shift assays , We show that alpha-p65MAb is suitable to study the activation state of NF-kappa B in cryosections of tissues.