The present invention is directed to nuclear factor .kappa.B (NF.kappa.B)-inducing factor polypeptides (NFIF polypeptides) which are capable of inducing NF.kappa.B. The present invention includes within its scope NFIF polypeptides, including NFIF-14b and NFIF-7a, DNA, including cDNA, encoding these polypeptides, and expression vectors capable of expressing NFIF polypeptides. Also included are methods and compositions for increasing NF.kappa.B induction in a patient, methods and compositions for lowering NF.kappa.B induction in a patient, methods for inhibiting inflammation, and methods for manufacutre of a medicament intended for the treatment and/or prevention of an NF.kappa.B-regulated inflammatory response. In addition, methods for determining whether a test compound inhibits or enhances the activity of NFIF polypeptides are provided.