The influence of vasoactive amines on interferon production in mice

Adrenergic inhibition of innate anti-viral response: PKA blockade of Type I interferon gene transcription mediates catecholamine support for HIV-1 replication

Type I interferons (IFN-alpha and -beta) play a key role in anti-viral immunity, and we sought to define the molecular mechanisms by which the sympathetic nervous system (SNS) inhibits their effects. In peripheral blood leukocytes and plasmacytoid dendritic cells (pDC2), induction of interferon anti-viral activity by double-stranded RNA (poly-I:C) or CpG DNA was substantially inhibited by norepinephrine and by pharmacologic activation of the cAMP/PKA signaling pathway. This effect was specific to Type I interferons and driven by PKA-mediated repression of IFNA and IFNB gene transcription. Luciferase reporter analyses identified tandem interferon response factor-binding sites in positive regulatory domains I and III of the IFNB promoter as a key target of PKA inhibition. PKA suppression of Type I interferons was associated with impaired transcription of interferon response genes supporting the "anti-viral state", and was sufficient to account for norepinephrine-induced enhancement of HIV-1 replication. Given the ubiquitous role of Type I interferons in containing viral replication, PKA-mediated inhibition of IFN transcription could explain the stimulatory effects of catecholamines on a broad range of viral pathogens.

Endotoxin-induced release of tumour necrosis factor and interferon in vivo is inhibited by prior adrenoceptor blockade

The effect of alpha- and beta-adrenoceptor blocking agents on endotoxin-induced release of tumour necrosis factor (TNF), and of interferon in the circulation of Corynebacterium parvum-treated mice was the subject of this study. TNF was quantified after injection of TNF containing heated serum (TNS) into Meth A sarcoma-bearing mice by determining colour, extent, and incidence of haemorrhagic necrosis. The release of TNF was weakly inhibited by the competitive alpha-blocker phentolamine and the beta-blocker propranolol. The non-competitive alpha-blocker phenoxybenzamine inhibited to a higher degree. Endotoxin-induced elicitation of growth-inhibiting principles into TNS was antagonized by propranolol and phenoxybenzamine. Administration of adrenaline before endotoxin inhibited the elicitation of TNF and growth-inhibitory activities, which indicates tachyphylaxis. The release of interferon was effectively inhibited by both alpha-adrenoceptor blockers but not by propranolol. The interferon was heat-labile. The results indicate that endotoxin-induced TNF and interferon are separate factors, elicited in different ways. As both alpha-blockers do not only inhibit reactions at the alpha-adrenergic receptor but also reactions at the serotonin receptor and in the case of phenoxybenzamine also at the choline receptor, it is suggested that endotoxin-induced release of the anti-tumour factors is controlled by reactions mediated by one or more of these receptors. It is suggested that the inhibition of TNF release by propranolol may be due to the membrane-stabilizing activity of this agent.

Duration of interferon inhibition following single and multiple injections of morphine

The increase in mouse serum interferon that occurs in response to poly I:C administration is markedly attenuated by injection of a narcotic preceding the polynucleotide challenge. A single injection of morphine is capable of inhibiting the mechanism(s) responsible for increasing serum interferon levels for a period of at least 9 days following the narcotic injection. Daily single injections of morphine for 5 or 10 days prior to poly I:C challenge do not amplify the extent of the decrease in serum interferon over that measured for a single injection, even though the amount of narcotic injected is increased on each successive day of the 5 or 10 day period. The implications of this relationship for the phenomenon of narcotic tolerance are evaluated and discussed as they relate to the immune processes.

The influence of substances changing the intracellular concentration of cyclic adenosine 3'5'-monophosphate on interferon synthesis in chick embryo cell culture

The influence of cyclic 3'5'-adenosine monophosphate (cAMP), adrenalin and theophylline on interferon synthesis induced by influenza B virus (Lee strain) in chick embryo cell cultures was studied. In 5-day-old cell culture, theophylline was shown to enhance the inhibiting effect of exogenous cAMP and adrenalin on interferon synthesis and in 1-day-old culture, on the contrary, to enhance interferon production whereas adrenaline under these conditions had no effect on interferon synthesis at all. In 5-day-old cultures the activity of adrenalin and theophylline was manifested when they were added to the maintenance medium not later than 4 hours postinfection, and was not associated with the influence on interferon inducer adsorption on to cells or on virus multiplication in sensitive systems. Treatment of cells with these substances had no effect on interferon release from the cells. In the concentration used, adrenalin and theophylline exerted no cytotoxic effect. Theophylline inhibited incorporation of 3H-uridine and 14C-leucine into the acid insoluble fraction of the infected cells in 1-day-old cultures, while in 5-day-old cultures this was observed only when adrenalin and theophylline were used together. It is suggested that endogenous cAMP is essential for control of interferon synthesis and that different cAMP levels in cells of different ages may be one of the causes of the varying potency for interferon synthesis in young and old cell cultures.