Ethnobotanical study on the medicinal plants in the Mainarde Mountains (central-southern Apennine, Italy).

ETHNOPHARMACOLOGICAL RELEVANCE: New documentation of the uses of plants in the popular medicine of the Mainarde Mountain, a protected area of the central-southern Apennine characterised by a high floristic richness, is here reported. MATERIALS AND METHODS: Field data were collected through semi-structured and open interviews with native People between 2011 and 2014. The plants were identified and vouchers specimens were scanned to create a Virtual Herbarium. The Ethnobotanicity Index (EI), the Relative Importance Index (RI) and the Fidelity Level Index (FL) were calculated. The plant uses surveyed in the study area were compared with those described in medical and ethnobotanical literature. RESULTS: Seventy-one interviews were conducted, the age range of the informants was between 21 and 98 years. The inventory included 106 taxa belonging to 45 families; among these, 87 were wild species and 20 were cultivated species. The uses recorded were 429, among these, 69.1% of the uses concerned internal applications to treat digestive system disorders, infections and respiratory system disorders mainly, while 31.9% concerned external applications, especially to treat skin/subcutaneous cellular tissue disorders and injuries. In particular, 17 new uses and 16 unusual and rarely mentioned plants are documented. CONCLUSION: The data collected support evidence on traditional uses for plant in the Apennine. Findings from medical flora and from new or rare medical uses reinforce the usefulness of such research efforts.

Long term treatment of pulmonary arterial hypertension with beraprost, an oral prostacyclin analogue.

OBJECTIVE: To evaluate the effects of one year's treatment with beraprost, an orally active prostacyclin analogue, in patients with severe pulmonary hypertension. PATIENTS: 13 patients with severe pulmonary hypertension. This was primary in nine, thromboembolic in three, and caused by Eisenmenger syndrome in one. METHODS: All patients underwent right heart catheterisation. Mean (SD) right atrial pressure was 5 (3) mm Hg, mean pulmonary artery pressure was 48 (12) mm Hg, cardiac index was 2.6 (0.8) l/min/m(2), and mixed venous oxygen saturation was 68 (7)%. Beraprost was started at the dose of 20 microgram three to four times a day (1 microgram/kg/day), increasing after one month to 40 microgram three to four times a day (2 microgram/kg/day), with further increases of 20 microgram three to four times a day in case of clinical deterioration. MAIN OUTCOME MEASURES: New York Heart Association (NYHA) functional class, exercise capacity measured by distance walked in six minutes, and systolic pulmonary pressure (by echocardiography) were evaluated at baseline, after one month's treatment, and then every three months for a year. RESULTS: After the first month of treatment, NYHA class decreased from 3.4 (0.7) to 2.9 (0.7) (p < 0.05), the six minute walking distance increased from 213 (64) to 276 (101) m (p < 0.05), and systolic pulmonary artery pressure decreased from 93 (15) to 85 (18) mm Hg (NS). One patient died after 40 days from refractory right heart failure, and another was lost for follow up at six months. The 11 remaining patients had persistent improvements in functional class and exercise capacity and a significant decrease in systolic pulmonary artery pressure in the period from 1-12 months. Side effects were minor. CONCLUSIONS: Oral administration of beraprost may result in long lasting clinical and haemodynamic improvements in patients with severe pulmonary hypertension.

Solitary fibrous tumour of the pleura: surgical treatment.

OBJECTIVE: Solitary fibrous tumours (SFT) of the pleura are rare tumours originated from the mesenchimal tissue underlying the mesothelial layer of the pleura. This tumours present unpredictable clinical course probably related to their histological and morphological characteristics. METHODS: Twenty-one patients affected by SFT of the pleura were referred to us for surgical resection from September 1984 to April 2000. They were 15 males and six females with median age of 51 (range 15--73) years. Nine patients (43%) were symptomatic and predominant clinical symptoms or signs were dyspnoea (19%), coughing (14.3%), chest pain (28.5%), finger clubbing (14.3%) and hypoglycaemia (14.3%). Hypoglycaemia was related to a pathological incretion of insulin-like growth factor 2 by the tumour. Chest radiograph and computed tomography of the chest revealed intra-thoracic homogeneous sharply delineated round or lobulated mass sometimes associated with ipsilateral pleural effusion (19%) or causing pulmonary atelectasis with opacification of the complete hemithorax (19%). Surgical excision required 14 posterolateral thoracotomies, six anterior thoracotomies and one video-assisted thoracoscopy. Thirteen tumours arose from visceral pleura and wedge resection was performed, seven tumours arose from parietal pleura and extrapleural resection was carried out without any chest-wall resection, one tumour growth within the upper left lobe and required lobectomy. Tumours weighted from 22 to 1942 g and measured from 22x12x8 to 330x280x190 mm. At cut section seven cases (34%) revealed focal necrosis and hemorrhagic zones and on light microscopy six cases (28.5%) were characterized by high mitotic count: characteristics related with uncertain clinical behaviour. Immuno-histochemical reactions were in all cases positive for CD34. RESULTS: In all our patients resections were complete. Paraneoplastic syndromes like hypoglycaemia and clubbing receded after surgery. No intraoperative or perioperative medical or surgical complications occurred. Median chest-drain duration timed 3 (range 2--5) days and median hospital stay was 5 (range 4--7) days. Perioperative mortality rate was 0%. Median follow-up was 68 (range 2--189) months: during this period patients were submitted to chest X-ray with 6-months interval to evaluate possible local recurrence. Only one patient experienced tumour recurrence after 124 months follow-up: the tumour was suspected after observation of finger clubbing. The tumour was detected and excised by redo-thoracotomy. CONCLUSIONS: Surgical resection of benign solitary fibrous tumours is usually curative, but local recurrences can occur years after seemingly adequate surgical treatment. Malignant solitary fibrous tumours generally have a poor prognosis. Clinical follow-up and radiological follow-up are indicated for both benign and malignant solitary fibrous tumours.

Soluble CD40 ligand induces beta-chemokine production by macrophages and resistance to HIV-1 entry.

CD40 ligand (CD40L) is a cell surface molecule of CD4(+)T cells that interacts with its receptor CD40 on antigen presenting cells to mediate thymus-dependent humoral immunity and inflammatory reactions. We report here that treating monocyte-derived macrophages (MDM) with a trimeric soluble form of CD40L (CD40LT) induced them to secrete high levels of the beta-chemokines RANTES, MIP-1alpha and MIP-1beta that are ligands for CCR5 and able to inhibit HIV-1 entry. CD40LT inhibited the entry of M-tropic HIV-1 reporter viruses. Furthermore, supernatants obtained from CD40LT-stimulated macrophages protected CEMx174-CCR5 cells from infection by HIV-1(JRFL)reporter virus. The inhibitory activity appeared to be due to beta-chemokines present in the supernatant, since pretreating them with a cocktail of antibodies to RANTES, MIP-1alpha and MIP-1beta neutralized the inhibitory activity of the supernatants. In addition, treating monocytes with CD40LT caused CCR5 and CD4 to be downregulated from the cell surface. In vivo, macrophages activated through CD40 could interfere with HIV replication.

Chemokine receptor regulation and HIV type 1 tropism in monocyte-macrophages.

Monocyte-macrophages can be productively infected by CCR5-specific, but not CXCR4-specific, HIV-1. This could be due either to the absence of this chemokine receptor in this cell lineage or to other, yet undefined cellular cofactors that modulate the coreceptor activity of the CXCR4 in these cells. To investigate the basis of macrophage tropism, we studied the expression of CCR5 and CXCR4, as well as several of the other CC chemokine receptors, on monocyte-macrophages at different stages of differentiation. We found that on fresh monocytes, CXCR4 was relatively abundant, but it fell to barely detectable levels in culture over 24 hr and maintained this low level of expression during differentiation in vitro. Some donor macrophages appeared to express CXCR4 at levels comparable to CCR5. In contrast, CCR5 expression was low on fresh monocytes but increased on in vitro differentiation. Taken together, the results show that monocyte-macrophage differentiation is associated with a differential expression of chemokine receptors that may contribute to, but does not fully account for, the selectivity of these cells to HIV entry. GM-CSF, a cytokine that induces macrophage differentiation, caused a rapid decrease in CXCR4 and CCR5 mRNA and was correlated with decreased ability to support HIV entry.

Simian immunodeficiency virus variants with differential T-cell and macrophage tropism use CCR5 and an unidentified cofactor expressed in CEMx174 cells for efficient entry.

The recent identification of coreceptors that mediate efficient entry of human immunodeficiency virus type 1 (HIV-1) suggests new therapeutic and preventive strategies. We analyzed simian immunodeficiency virus (SIV) entry cofactors to investigate whether the macaque SIV model can be used as an experimental model to evaluate these strategies. Similar to primary HIV-1 isolates, a well-characterized molecular clone, SIVmac239, which replicates poorly but efficiently enters into rhesus alveolar macrophages and an envelope variant, SIVmac239/316Env, with an approximately 1,000-fold-higher replicative capacity in macrophages used the beta-chemokine receptor CCR5 for efficient entry. The transmembrane portion of 316Env allowed low-level entry into cells expressing CCR1, CCR2B, and CCR3. A single amino acid substitution in the V3 loop of SIVmac239/316Env, 321P-->S, impaired the ability to enter into the T-B hybrid cell line CEMx174 but had relatively little effect on entry into primary cells and HOS.CD4 cells expressing CCR5. Although CEMx174 cells do not express CCR5, most SIVmac variants entered this hybrid cell line efficiently but did not enter the parental T-cell line CEM. It seems likely that CEMx174 cells express an as-yet-unidentified, perhaps B-cell-derived cofactor which allows efficient entry of SIVmac.

Identification of a major co-receptor for primary isolates of HIV-1.

Entry of HIV-1 into target cells requires cell-surface CD4 and additional host cell cofactors. A cofactor required for infection with virus adapted for growth in transformed T-cell lines was recently identified and named fusin. However, fusin does not promote entry of macrophage-tropic viruses, which are believed to be the key pathogenic strains in vivo. The principal cofactor for entry mediated by the envelope glycoproteins of primary macrophage-tropic strains of HIV-1 is CC-CKR-5, a receptor for the beta-chemokines RANTES, MIP-1alpha and MIP-1beta.

Mutational analysis of cell cycle arrest, nuclear localization and virion packaging of human immunodeficiency virus type 1 Vpr.

Human immunodeficiency virus type 1 Vpr is a virion-associated, regulatory protein that is required for efficient viral replication in monocytes/macrophages. The protein is believed to act in conjunction with the Gag matrix protein to allow import of the viral preintegration complex in nondividing cells. In cells, Vpr localizes to the nucleus. Recently, we showed that Vpr prevents the activation of p34cdc2-cyclin B. This results in arrest of Vpr-expressing cells in the G2/M phase of the cell cycle. Here, we use a panel of expression vectors encoding Vpr molecules mutated in the amino-terminal alpha-helical region, the central hydrophobic region, or the carboxy-terminal basic region to define the functional domains of the protein. The results showed cell cycle arrest was largely controlled by the carboxy-terminal basic domain of the protein. In contrast, the amino-terminal alpha-helical region of Vpr was required for nuclear localization and packaging into virions. The carboxy terminus appeared to be unnecessary for nuclear localization. In the alpha-helical region, mutation of Ala-30 to Pro resulted in a protein that localized to the cytoplasm. Surprisingly, fusion of Vpr to luciferase resulted in a molecule that failed to localize to the nucleus. In addition, we show that simian immunodeficiency virus Vpr, but not Vpx, induces G2 arrest. We speculate that Vpr has two sites for interaction with cellular factors: one in the alpha-helical region that specifies nuclear localization and one in the carboxy-terminal domain that is required for Cdc2 inhibition.

Human immunodeficiency virus type 1 viral protein R (Vpr) arrests cells in the G2 phase of the cell cycle by inhibiting p34cdc2 activity.

The Vpr accessory gene product of human immunodeficiency virus types 1 and 2 and simian immunodeficiency virus is believed to play a role in permitting entry of the viral core into the nucleus of nondividing cells. A second role for Vpr was recently suggested by Rogel et al. (M. E. Rogel, L. I. Wu, and M. Emerman, J. Virol. 69:882-888, 1995), who showed that Vpr prevents the establishment in vitro of chronically infected HIV producer cell lines, apparently by causing infected cells to arrest in the G2/M phase of the cell cycle. In cycling cells, progression from G2 to M phase is driven by activation of the p34cdc2/cyclin B complex, an event caused, in part, by dephosphorylation of two regulatory amino acids of p34cdc2 (Thr-14 and Tyr-15). We show here that Vpr arrests the cell cycle in G2 by preventing the activation of the p34cdc2/cyclin B complex. Vpr expression in cells caused p34cdc2 to remain in the phosphorylated, inactive state, p34cdc2/cyclin B complexes immunoprecipitated from cells expressing Vpr were almost completely inactive in a histone H1 kinase assay. Coexpression of a constitutively active mutant p34cdc2 molecule with Vpr relieved the G2 arrest. These findings strongly suggest that Vpr arrests cells in G2 by preventing the activation of the p34cdc2/cyclin B complex that is required for entry into M phase. In vivo, Vpr might, by preventing p34cdc2 activation, delay or prevent apoptosis of infected cells. This would increase the amount of virus each infected cell produced.

Interferon gamma upregulates its own gene expression in mouse peritoneal macrophages.

Interferon gamma (IFN-gamma) exerts a variety of immunoregulatory effects on several cell targets. It is generally assumed that IFN-gamma is specifically produced by T and large granular lymphocytes. In this study, we show that IFN-gamma is constitutively expressed in resting mouse peritoneal macrophages (PM). Treatment of PM with cycloheximide results in a significant accumulation of IFN-gamma mRNA, suggesting that a short-lived IFN-gamma mRNA accumulates when protein synthesis is inhibited. Moreover, treatment of PM with IFN-gamma also results in a clear-cut accumulation of this mRNA. This effect is not observed in murine lymphocytes from mesenteric lymph nodes (which instead produce IFN-gamma after phytohemagglutinin treatment) and in mouse cell lines. The treatment of PM with IFN-gamma also results in secretion of IFN-gamma after 24-48 h. The upregulation of IFN-gamma expression is also found in PM from anti-asialo GM1-treated nude mice. We suggest that the ability of PM to produce this IFN-gamma is indicative of an autocrine mechanism. The macrophage IFN-gamma may play a role in the regulation of cell differentiation and immune response.

Enhanced production of LPS-induced cytokines during differentiation of human monocytes to macrophages. Role of LPS receptors.

In vitro cultivated human monocytes isolated from normal peripheral blood show a time-dependent differentiation into macrophages characterized by an increased expression of transferrin receptors, CD11/CD18, and CD14 Ag. We measured the secretion of TNF-alpha and IL-6 in freshly isolated monocytes and in differentiated macrophages after LPS treatment. Differentiated macrophages produced significantly higher amounts of TNF-alpha and IL-6 than freshly isolated monocytes. This increased secretion was not a result of an enhanced accumulation of TNF-alpha and IL-6 mRNA, as comparative levels of these transcripts were found in both cell types after LPS treatment. Furthermore, LPS did not induce an antiviral state to VSV3 in monocytes, but it reduced by 3 to 5 log10 the virus yield in differentiated macrophages. The addition of antibodies to IFN-beta completely inhibited the LPS-induced antiviral state to VSV, but antibodies to IFN-alpha, TNF-alpha, or IL-6 were ineffective. A marked accumulation of IFN-beta mRNA was found in both cell types after LPS treatment. Binding experiments with FITC-LPS revealed a slightly higher overall binding affinity for LPS in freshly explanted monocytes as compared with differentiated macrophages, even though the maximal binding was higher in macrophages. In both cell types, the LPS binding was partially inhibited by antibodies to CD14. These results demonstrate that: 1) in vitro differentiation of human monocytes to macrophages leads to an enhanced LPS response in terms of (a) progressive increase of IL-6/TNF-alpha production and (b) acquisition of an IFN-beta mediated antiviral state; 2) this enhanced response to LPS, largely CD14-independent, is not linked to any increased accumulation of cytokine mRNA, but is probably a result of an increased synthesis and/or secretion of these cytokines.

Cyclic AMP-mediated inhibition of vesicular stomatitis virus and herpes simplex virus replication in mouse macrophage-like cells.

In this study, we have analysed the effects of cAMP inducers on the multiplication of vesicular stomatitis virus (VSV) and herpes simplex virus type 1 (HSV-1) in mouse macrophage-like cells. The addition of dibutyryl cAMP (dB-cAMP) or cholera toxin to resting peritoneal macrophages aged in vitro or P388D1 cells resulted in a 10- to 100-fold reduction of VSV yield compared to control cultures. In contrast, no cAMP-dependent inhibition was found in VSV-infected L929 cells. In macrophage-like cells, the dB-cAMP-induced antiviral state was not inhibited by antibodies to interferon (IFN)-alpha/beta and did not correlate with any increase in the intracellular levels of 2-5 oligo(A) synthetase. Dibutyryl cAMP did not inhibit virus yields in mouse macrophages infected with encephalomyocarditis virus. In P388D1 cells, the addition of dB-cAMP resulted in an approximately 10-fold inhibition of HSV-1 replication with respect to control cultures, as evaluated both by TCID50 and plaque assays on Vero cells. Dibutyryl cAMP did not affect VSV binding or entry into mouse macrophages and the cAMP-mediated anti-VSV state was significantly reduced by inhibitors of protein kinase C (i.e. staurosporine and H7). These data suggest that macrophages may acquire resistance to infection by VSV and HSV-1 after treatment with cAMP inducers. This cAMP-mediated antiviral activity does not depend on the modulation of the endogenous IFN system, suggesting that macrophages exhibit multiple resistance mechanisms (i.e. IFN-dependent and IFN-independent) to maintain their intrinsic antiviral activity.

Specific interferon genes are expressed in individual cells in the peritoneum and bone marrow of normal mice.

The use of a highly sensitive method of in situ hybridization capable of detecting one copy of IFN mRNA per cell showed that from 20-50% of the cells from the peritoneum and bone marrow of both normal pathogen-free and axenic mice exhibited grain counts significantly greater than background levels following hybridization with riboprobes specific for the mouse interferon-alpha (IFN-alpha), IFN-beta, or IFN-gamma genes. Labeling was shown to be specific, as the labeled probe was displaced by a 200-fold excess of the specific unlabeled probe but not by a 200-fold excess of an unrelated probe. Grain counts were reduced to background levels when cells were pretreated with ribonuclease prior to in situ hybridization. The extent of labeling with either IFN-alpha or IFN-beta-specific probes increased following i.v. inoculation of mice with the IFN-inducer Newcastle disease virus (NDV) whereas the degree of labeling observed with a probe specific for beta-actin remained unchanged. No significant differences were observed in the number of bone marrow or peritoneal cells that expressed IFN-alpha or IFN-beta mRNA from either high (C57B1/6) or low (BALB/c) IFN-producing strains of mice. The majority of IFN-alpha and IFN-beta-containing cells from both the bone marrow and peritoneum of normal pathogen-free and axenic mice resembled monocytes morphologically, whereas the majority of IFN-gamma mRNA-containing cells resembled small lymphocytes. In addition, in the bone marrow a number of large cells which resembled megacaryocytes were found to express high levels of IFN-alpha mRNA. Nuclear run-on assays showed that IFN-alpha and IFN-beta genes were actively transcribed in both bone marrow and peritoneal cells from normal and axenic mice. Low levels of de novo IFN-gamma RNA synthesis were detected in the nuclei of peritoneal cells only. The expression of IFN genes in individual cells in the tissues of normal animals may constitute a basis for the regulation of both homeostasis and host defense against virus infection and neoplastic cells.

Spontaneous expression of interferon genes in murine peritoneal macrophages: modulation during the in vitro aging.

The expression of interferon (IFN)-beta gene and its modulation during in vitro "aging" was studied in unstimulated peritoneal macrophages (PM) explanted from lipopolysaccharide (LPS)-responsive (Lps(h)) and LPS-hyporesponsive (Lps(d)) mice. A strong direct correlation between the LPS response of PM and their capacity to express low levels of IFN-beta was found. Moreover, the decay of antiviral state during in vitro cultivation was correlated with the turnover of IFN-beta mRNA. In the light of the multiple biologic effect of IFN, the constitutive expression of IFN-beta gene in PM can play a crucial role not only in the restriction of viral replication, but also in the modulation of cell differentiation and immune response.

Posttranscriptional regulation of interferon mRNA levels in peritoneal macrophages.

Low levels of beta interferon (IFN) mRNA are transcribed in freshly explanted murine peritoneal macrophages. Nuclear runoff transcription assays show that this "constitutive" IFN-beta-mRNA transcription does not increase in macrophages treated either with lipopolysaccharide or with IFN-gamma, which induce a marked accumulation of this mRNA and greatly increase IFN secretion. Therefore, these agents promote accumulation of IFN-beta mRNA by posttranscriptional mechanisms. The IFN-alpha 2 gene is also constitutively transcribed by macrophages, but the corresponding mRNA does not accumulate in lipopolysaccharide-treated cells.

Expression of interferon genes in murine macrophages: Possible role of endogenous interferon in the modulation of cell differentiation.

The expression of interferon (IFN)-ß gene was studied in mouse peritoneal macrophages (PM) harvested from normal mice (lps ( n )) or LPS-hyporesponsive mice (lps ( d )). A strong direct correlation between the LPS response of PM and their capacity to expressing basal levels of IFN was found. The results suggest that the constitutive expression of IFN-ß gene can play an important role not only in the resistance to viral infection but also in the modulation of cell differentiation.

Effects of different biological response modifiers on interferon expression in bacterial lipopolysaccharide (LPS)-responsive and LPS-hyporesponsive mouse peritoneal macrophages.

We have previously shown that the antiviral state of explanted mouse peritoneal macrophages (PM) decays during in vitro culture and that this decay is much more rapid in Lpsd PM than it is in Lpsn PM. Moreover, Lpsn PM can transfer the antiviral state to other cells, whereas Lpsd PM cannot. In vitro treatment of Lpsn PM with different agents [i.e., bacterial lipopolysaccharide (LPS), interferon (IFN)-gamma, tumour necrosis factor (TNF)-alpha, macrophage colony-stimulating factor (M-CSF) and antibody to Mac-1 antigen] induced an antiviral state to vesicular stomatitis virus (VSV) which was inhibited by antibodies to IFN-beta. Treatment of Lpsn PM with LPS or IFN-gamma resulted in greater accumulation of IFN-beta mRNA, whereas no change in the barely detectable levels of IFN-alpha mRNA was observed. Marked accumulation of IFN-beta mRNA was also observed in PM after TNF-alpha treatment. M-CSF and IFN-gamma (but not LPS) also induced an IFN-mediated antiviral state in Lpsd PM. Low levels of spontaneous transcription of IFN-beta mRNA were detected in nuclei from Lpsd PM. Treatment of Lpsd PM with IFN-gamma for 3 h resulted in the accumulation of IFN-beta mRNA without any concomitant increase in the transcription of the IFN-beta gene, as determined by run-on transcription assays with isolated nuclei. The addition of as little as I international unit/ml of IFN-gamma to PM resulted in a 100-fold inhibition of VSV yield. As antibodies to IFN-alpha/beta inhibited only a portion of the IFN-gamma-induced antiviral state, such an antiviral state might reflect the synergism between IFN-gamma and endogenous IFN-beta. In fact, the addition of low doses of both IFN-gamma and IFN-beta to either Lpsn or Lpsd PM resulted in synergistic antiviral effects. In vivo treatment of Lpsd mice with granulocyte-macrophage (GM)-CSF, M-CSF, IFN-gamma or Newcastle disease virus rendered peritoneal cells capable of transferring an antiviral state. These results indicate that (i) various stimuli can induce IFN-beta production by PM, (ii) Lpsd PM spontaneously transcribe low levels of IFN-beta mRNA, even though they cannot transfer an antiviral state, (iii) different stimuli, but not LPS, induce a normal IFN response in Lpsd PM, (iv) IFN-gamma increases the accumulation of IFN-beta mRNA in Lpsd PM by post-transcriptional mechanisms and (v) IFN-gamma may act synergistically with endogenous IFN-beta in inducing a potent antiviral state to VSV in PM.

Activators of protein kinase C enhance accumulation of interferon-beta mRNA in murine cell lines.

Murine C127 fibroblasts carrying an expression vector for a human interferon gene (HuIFN-beta, under the control of a constitutive promoter) can be induced to produce murine (Mu) IFN by double-stranded (ds) RNA or virus infection. Fibroblasts treated with the protein kinase C activators 1-oleyl-2-acetylglycerol (OAG) or phorbol-12-myristate-13-acetate (PMA) secrete greater amounts of MuIFN than untreated cells, but the same amount of HuIFN-beta. Accordingly, the level of MuIFN-beta mRNA increases in the presence of protein kinase C activators whereas that of HuIFN-beta mRNA is unchanged. In time course experiments after induction with dsRNA, accumulation of MuIFN-beta mRNA is observed within 30 min in the presence of OAG, when this mRNA cannot be detected in control cells. The protein kinase C activators increase accumulation of MuIFN-beta mRNA, even in the presence of the inhibitor of protein synthesis cycloheximide. A similar increase in MuIFN-beta mRNA is observed in C243 fibroblasts treated with phorbol-12-myristate-13-acetate, but not in parental C127 cells. These findings suggest that protein kinase C does not promote synthesis of regulatory factors controlling transcription of IFN mRNA, but that it may be directly or indirectly involved in activation of such factors in some murine cell lines.