Orphanin FQ/nociceptin interactions with the immune system in vivo: Gene expression changes in lymphoid organs and regulation of the cytokine response to staphylococcal enterotoxin A

Orphanin FQ/nociceptin (OFQ/N) is a neuropeptide implicated in immunomodulation. Here, we show that endogenous and exogenous OFQ/N modulated the cytokine response to the bacterial superantigen staphylococcal enterotoxin A (SEA). Specifically, OFQ/N enhanced TNF alpha and IFN gamma transcripts in the spleen when injected prior to SEA challenge. Moreover, mice lacking the OFQ/N precursor gene showed diminished TNF alpha and IFN gamma mRNA induction in the spleen following SEA challenge. In addition, mRNA levels of ppOFQ/N and the OFQ/N receptor, NOP, were altered in thymus and spleen after SEA challenge. Overall, this suggests that the OFQ/N system can influence immune function and is itself influenced by immune stimuli. (c) 2006 Elsevier B.V. All rights reserved.