We have studied the effects of interferon (IFNs) alpha and gamma on the regulation and expression of laminin (LMN) and a 32 kD laminin binding protein (LPB-32) in cultured human umbilical vein endothelial cells (HUVEC) and human foreskin fibroblast (FS-4) cells. We show that IFNs increased immunofluorescent staining for LMN and LPB-32. In HUVEC, B1 and B2 chain immunoprecipitated proteins were enhanced in the extracellular (released) fraction by IFN-alpha, but were decreased by IFN-gamma. In intracellular (cell-associated) fractions, both B chains were increased, especially by IFN-gamma. In situ hybridization of FS-4 cells demonstrated increased B2 chain mRNA in the presence of IFNs. Reverse transcription-polymerase chain reaction amplification (RT-PCR) indicated that B1 chain mRNA was increased by both IFNs in HUVEC, and by IFN-gamma in FS-4. The increased synthesis of LMN and LBP-32 may be important in promoting wound healing and angiogenesis.