High Levels Of IFN-alpha Research Articles

Seroconversion stages COVID19 into distinct pathophysiological states.

COVID19 is a heterogeneous medical condition involving diverse underlying pathophysiological processes including hyperinflammation, endothelial damage, thrombotic microangiopathy, and end-organ damage. Limited knowledge about the molecular mechanisms driving these processes and lack of staging biomarkers hamper the ability to stratify patients for targeted therapeutics. We report here the results of a cross-sectional multi-omics analysis of hospitalized COVID19 patients revealing that seroconversion status associates with distinct underlying pathophysiological states. Low antibody titers associate with hyperactive T cells and NK cells, high levels of IFN alpha, gamma and lambda ligands, markers of systemic complement activation, and depletion of lymphocytes, neutrophils, and platelets. Upon seroconversion, all of these processes are attenuated, observing instead increases in B cell subsets, emergency hematopoiesis, increased D-dimer, and hypoalbuminemia. We propose that seroconversion status could potentially be used as a biosignature to stratify patients for therapeutic intervention and to inform analysis of clinical trial results in heterogenous patient populations.

Abstract 2322: Intratumoral treatment with a highly interferogenic TLR9 agonist reverts tumor escape from PD-1 blockade

Abstract The induction of tumor specific T cell exhaustion by the PD-1/PDL-1 pathway is an important mechanism of immune escape in cancer. Therapies blocking or reversing T cell exhaustion can produce durable responses in metastatic cancers including melanoma, NSCLC, renal carcinoma and bladder cancer. However, only a small subset of patients experience response upon anti-PD-1/PDL-1 treatment, whereas many others are refractory, showing no response at all. Thus, a key challenge is transforming a non-permissive tumor microenvironment into an immunologically competent one, in order to increase the frequency of patients with durable responses to PD-1/PDL-1 blockade. We have characterized a mouse tumor model with a reproducible dichotomous response to anti-PD-1 treatment analogous to that observed in human cancers. We show that the ability of tumors to be rejected in response to anti-PD-1 treatment is highly correlated with degree of T cell infiltration, expression of Type I IFNs and B cell activation signatures, in whole tumors and in tumor infiltrating leukocytes. We then evaluate whether immunomodulation by intratumoral vaccination with a TLR9 agonist, SD-101, would affect rate of response to anti-PD-1 blockade. SD-101, is a CpG-C class oligonucleotide, optimized to induce both very high levels of IFN-alpha as well as maturation of dendritic cells and B cells. Intratumoral injection of SD-101 in tumor bearing mice undergoing anti-PD-1 therapy leads tumor rejection in 100% of treated mice versus a 20% tumor rejection in mice treated with anti-PD-1 blockade alone. SD-101 alone, although efficacious in reducing tumor growth, did not lead to durable tumor rejection. Immune cell subset depletion studies implicate CD8, but not CD4, T cells in the rejection of tumors treated with anti-PD1 plus SD-101. T cell response generated in one flank by IT injection of SD-101 synergizes with systemic PD-1 blockade to induce rejection of unvaccinated distal tumors. In addition, we show that mice receiving systemic anti-PD-1 plus SD-101 have a higher percentage of CD8+ T cells infiltrating the tumors when compared to anti-PD-1 responders, anti-PD-1 non-responders or SD-101 given alone. Infiltrating CD4 and CD8 T cells in tumors with combination treatment, show a higher proliferative capacity and a higher frequency of cells producing both TNF-a and IFN-g than tumors responding to anti-PD-1 monotherapy. This demonstrates the potential for SD-101 to significantly enhance the frequency of responders to anti-PD-1 therapy by increasing the number and functionality of anti-tumor T cells within the tumor. Citation Format: Shu Wang, Jose Campos, Edwina Naik, Crain Chad, Gallotta Marilena, Coffman Robert L., Cristiana Guiducci. Intratumoral treatment with a highly interferogenic TLR9 agonist reverts tumor escape from PD-1 blockade. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2322.

Plasmacytoid dendritic cell depletion augments CD8 T cell IFN-γ associated atherogenic responses in a mouse model of atherosclerosis. (147.18)

Abstract Plasmacytoid dendritic cells (pDC) have been shown to play a pivotal immunogenic role in viral immune responses by releasing high IFN-alpha levels upon TLR9 activation. However, evidence is culminating that pDC also play a major role in inducing immune tolerance in chronic low grade inflammation. In this study we set out to address effects of pDC depletion on atherosclerosis development. Carotid artery lesions were induced in LDLr-/- mice by perivascular collar placement. To study effects of pDC depletion on atherogenesis, a pDC depleting antibody, 120G8, was administered daily for 4 weeks. GL113 mAb was used as isotype control. pDC depletion resulted in exacerbated atherosclerosis, characterized by an increased lesion CD3+ T cell infiltration. FACS analysis showed an increase in CD3+ T cell numbers in spleen and lymph nodes with a concurrent shift towards CD8+ T cells. This was paralleled by strongly elevated plasma IFN-γ levels. Moreover, immature but not mature pDC from spleen of atherosclerotic mice expressed increased levels of IDO and PD-L1 compared to pDC from non-atherosclerotic mice. Finally, we found that pDC isolated from human UAP/SAP patients displayed reduced IFNalpha expression, while intralesional expression of IFNalpha was unaltered at later stages of disease progression. In conclusion, our data demonstrate that immature pDC act atheroprotective by dampening CD8+ T cell responses and keeping Th2/Th1 responses in check.

Gene-Gene-Sex Interaction in Cytokine Gene Polymorphisms Revealed by Serum Interferon Alpha Phenotype in Juvenile Dermatomyositis

To detect genetic polymorphisms associated with high serum interferon alpha (IFN-alpha) levels in juvenile dermatomyositis (JDM) and explore interactions in associated polymorphisms. Eighty-five children of European ancestry with definite/probable JDM were studied. Selected genetic polymorphisms that were associated with high IFN-alpha levels in 12 untreated patients with newly diagnosed JDM were genotyped in a validation cohort of 73 children with JDM and analyzed for gene-gene and gene-sex interactions. Untreated children with newly diagnosed JDM carrying both the osteopontin (OPN) rs28357094G and tumor necrosis factor alpha (TNF-alpha)-308 A alleles had significantly increased serum IFN-alpha levels. These 2 polymorphisms were genotyped in the validation cohort, and the OPN rs28357094G allele was more common in female subjects with JDM (odds ratio=3.97, P=.012). This OPN allele was most strongly enriched in female carriers of TNF-alpha-308A as compared with male carriers of TNF-alpha-308A (odds ratio>9.0; P=7.2x10(-3)). These data support a complex gene-gene-sex interaction between the OPN and TNF-alpha promoter regions in JDM, defining a high serum IFN-alpha subgroup within JDM. This suggests pathogenic synergy between the OPN and TNF-alpha loci in female subjects with JDM, which may underlie some of the increased incidence of this condition in girls.

Interferon-α and Interleukin-6 in SLE serum induce the differentiation and maturation of dendritic cells derived from CD34+ hematopoietic precursor cells

The objective of this study was to investigate the effects of the cytokines IFN-alpha, IL-6 and IL-10 present in the serum of systemic lupus erythematosus (SLE) patients on the differentiation and maturation of DCs derived from CD34(+) hematopoietic precursor cells (HPCs). CD34(+) HPCs cultured in SLE serum containing elevated levels of IFN-alpha or IL-6 differentiated into DCs showing an increased expression of HLA-DR, CD80 and CD86, decreased IL-12 secretion along with increased IL-10 production, and an increased ability to stimulate allogenic T-cell proliferation, compared with DCs cultured in normal serum. DCs cultured with high levels of IFN-alpha increased the proportion of both CD3(+)CD8(-)IFN-gamma(+) and CD3(+)CD8(+)IFN-gamma(+) T-cell subsets, and increased the production of IFN-gamma in the allogenic MLR. DCs cultured with high levels of IL-6 decreased the proportion of both IFN-gamma(+) T-cell subsets, and decreased the secretion of IFN-gamma, but increased the production of IL-10. The IL-10 present in SLE serum did not significantly alter the phenotype or function of the DCs. IFN-alpha and IL-6 present in SLE serum induce CD34(+) HPCs to differentiate into DCs with different regulatory effects on T-cell differentiation, which might be involved in the initiation and maintenance of SLE.

Toll-like Receptor 7 Selective Synthetic Oligoribonucleotide Agonists: Synthesis and Structure−Activity Relationship Studies

We previously reported a novel class of stabilized immune-modulatory RNA (SIMRA) compounds that activates TLR8 or both TLR7 and TLR8 depending on the nucleotide composition and chemical modifications incorporated. In the present study, to identify TLR7-selective agonists, we designed and synthesized novel SIMRA compounds with varying sequence compositions substituting 7-deaza-G for natural guanosine and studied immune-stimulatory activity in cell-based assays and in vivo in mice. SIMRA compounds activated NF-kappaB in HEK293 cells expressing TLR7 and induced cytokine production in mouse spleen cells and human PBMCs and higher levels of IFN-alpha in human pDCs, which correlated with TLR7 activation. Subcutaneous administration of SIMRA compounds to mice increased serum cytokine levels. TLR knockout mouse studies showed that both TLR7 and MyD88 are required for activity of SIMRA compounds. The presence of a 5'-AA/CN (A > C and N = U/C/7-deaza-G) and/or C/AUU-3' (C > A) trinucleotide at the 5'- and 3'-ends of SIMRA compound along with a 5'-AN(1)N(2)UG1A-3' (N(1) = A/C; N(2) = U/C/7-deaza-G) or UG1AZ(1)G1Z(2)UU (Z(1) = A < C; Z(2) = C < A) motif confers TLR7 selectivity over other sequence compositions. In conclusion, we have designed and synthesized novel SIMRA compounds that selectively act as agonists of TLR7.

Interferon‐Related Transcriptome Alterations in the Cerebrospinal Fluid Cells of Aicardi‐Goutières Patients†

Aicardi-Goutières syndrome (AGS) is a rare interferon (IFN)-related encephalopathy with onset during the first year of life. AGS, is clinically characterized by progressive microcephaly, bilateral basal ganglia calcification, cerebral atrophy, cerebrospinal fluid (CSF), lymphocytosis, delayed development of psychomotor abilities with pyramidal-extrapyramidal syndrome and mimics congenital viral infections. Microarray analysis examining the expression of 18 880 human genes has been applied to the CSF lymphocytes of 20 AGS cases (age 4.5 +/- 4.4 years, mean +/- standard deviation) characterized by high IFN-alpha levels in CSF and 20 matched controls (age 4.4 +/- 4.3 years, mean +/- standard deviation). Gene-expression data reveal significant differences between AGS cases and controls for all controls and 18 AGS cases. The two AGS cases unclassified as compared with controls were both older than 7 years. AGS cases presented upregulation of genes involved in IFN-dependent pathways and lymphocyte functions, paralleled by the downregulation of genes encoding for angiopoietic activities. The cystatin F and DNAJ genes, having a negative feedback on IFN pathways, underwent a progressive age-related increase in their expression. These gene-expression signature parallels a progressive attenuation of clinical symptoms with age. Obtained results provide evidence that exposure to IFN-alpha is harmful for developing brain.

Dysfunctional CD4+,CD25+ regulatory T cells in untreated active systemic lupus erythematosus secondary to interferon‐α–producing antigen‐presenting cells

To explore whether there are extrinsic factors that impair the suppressive function of CD4+,CD25+ regulatory T cells in patients with untreated active systemic lupus erythematosus (SLE). We studied 15 patients with untreated active SLE, 10 patients with SLE in remission, and 15 healthy control subjects. Percentages of CD4+,CD25+,FoxP3+ Treg cells and levels of forkhead box P3 (FoxP3) protein were analyzed by flow cytometry. Expression of messenger RNA (mRNA) for FoxP3 in purified Treg cell populations was assessed by real-time polymerase chain reaction analysis. Experiments examining Treg cell function in SLE were designed to distinguish primary from secondary T cell dysfunction. Levels of interferon-alpha (IFNalpha) in supernatants from the function assays were determined with an IFN-stimulated response element-luciferase reporter assay. The percentage of CD4+,CD25+, FoxP3+ cells in peripheral blood was significantly increased in SLE patients as compared with controls (mean +/- SEM 9.11 +/- 0.73% versus 4.78 +/- 0.43%; P < 0.0001). We found no difference in FoxP3 expression at either the mRNA or protein level in any CD4+,CD25+ T cell subset from SLE patients as compared with controls. Antigen-presenting cells (APCs) from SLE patients were responsible for decreased Treg cell activity and could also render dysfunctional Treg cells from healthy control subjects. CD4+,CD25+ Treg cells from SLE patients exhibited normal suppressive activity when cultured with APCs from healthy controls. A partial Treg cell blockade effect was induced by the high levels of IFNalpha derived from SLE patient APCs. We suggest that blockade of Treg cell-mediated suppression by IFNalpha-producing APCs in SLE patients may contribute to a pathogenic loss of peripheral tolerance in this disease.

Intracellular signal transduction of interferon on the suppression of haematopoietic progenitor cell growth.

Interferon (IFN)-alpha and IFN-gamma suppress the growth of haematopoietic progenitor cells. IFN-alpha activates Janus kinase-1 (Jak1) and Tyrosine kinase-2 (Tyk2), followed by the phosphorylation of the signal transducers and activators of transcription, Stat1 and Stat2. IFN-gamma activates Jak1 and Jak2, followed by the activation of Stat1. Activated Stats bind the promoter regions of IFN-inducible genes. We evaluated the role of Tyk2 and Stat1 in the IFN-mediated inhibition of haematopoietic progenitor cell growth. While IFN-alpha (1000 U/ml) suppressed the number of granulocyte-macrophage colony-forming units (CFU-GM) or erythroid burst-forming units (BFU-E) from wild-type mouse bone marrow cells, this suppression was partially inhibited by a deficiency in Tyk2 and completely inhibited by a deficiency in Stat1. High levels of IFN-alpha (10,000 U/ml) suppressed the CFU-GM or BFU-E obtained from Stat1-deficient mice, but did not suppress this growth in cells from Tyk2-deficient mice. Stat1 was phosphorylated by IFN-alpha in Tyk2-deficient cells, although the level of phosphorylation was weaker than that observed in wild type mice. Thus, the inhibitory signal on haematopoietic progenitor cells mediated by IFN-alpha may be transduced by two signalling pathways, one regulated by Tyk2 and the other dependent on Stat1. IFN-gamma also suppressed the number of CFU-GM or BFU-E, and this pathway was mediated by IFN-gamma in a Stat1-dependent manner, independently of Tyk2.

Activation of tumor antigen-specific cytotoxic T lymphocytes (CTLs) by human dendritic cells infected with an attenuated influenza A virus expressing a CTL epitope derived from the HER-2/neu proto-oncogene.

The development of cancer vaccines requires approaches to induce expansion and functional differentiation of tumor antigen-specific cytotoxic T lymphocyte (CTL) effectors which posses cytolytic capability and produce cytokines. Efficient induction of such cells is hindered by the poor immunogenicity of tumor antigens and by the poor transduction efficiency of dendritic cells (DCs) with current nonreplicating vectors. We have investigated the use of influenza A virus, a potent viral inducer of CTLs, as a vector expressing the immunodominant HER-2 CTL epitope KIF (E75). For this purpose, an attenuated influenza A/PR8/34 virus with a truncated nonstructural (NS1) gene was generated containing the E75 epitope in its neuraminidase protein (KIF-NS virus). Stimulation of peripheral blood mononuclear cells from healthy donors and of tumor-associated lymphocytes from ovarian and breast cancer patients with DCs infected with KIF-NS virus (KIF-NS DC) induced CTLs that specifically recognized the peptide KIF and HER-2-expressing tumors in cytotoxicity assays and secreted gamma interferon (IFN-gamma) and interleukin-2 at recall with peptide. Priming with KIF-NS DCs increased the number of E75(+) CD45RO(+) cells by more than 10-fold compared to nonstimulated cells. In addition, KIF-NS virus induced high levels of IFN-alpha in DCs. This is the first report demonstrating induction of human epitope-specific CTLs against a tumor-associated antigen with a live attenuated recombinant influenza virus vector. Such vectors may provide a novel approach for tumor antigen delivery, lymphocyte activation, and differentiation in human cancer vaccine development.

CpG-A-induced monocyte IFN-gamma-inducible protein-10 production is regulated by plasmacytoid dendritic cell-derived IFN-alpha.

Unmethylated CpG motifs in bacterial DNA or synthetic oligodeoxynucleotides (ODN) are known for inducing a Th1 cytokine/chemokine environment, but the mechanisms regulating this have been unclear. Recent studies have defined two classes of CpG ODN, CpG-A ODN that induce plasmacytoid dendritic cells (pDC) to secrete very high levels of IFN-alpha, and CpG-B ODN that induce only low levels of IFN-alpha production, but strongly activate B cells. We now demonstrate that a CpG-A ODN directly activates pDC secretion of IFN-alpha and other soluble factors that secondarily induce purified monocytes to secrete high levels of the Th1-promoting chemokine IFN-gamma-inducible protein-10 (IP-10). Cell contact between the monocytes and pDC is not required for this interaction. IFN-alpha is necessary, but only partially sufficient, for this indirect CpG-induced monocyte IP-10 production. Although CpG ODN induce human PBMC to make only very slight amounts of IFN-gamma, we find that these low concentrations synergize with IFN-alpha for inducing monocyte production of IP-10. These studies provide a better understanding of the mechanisms through which CpG ODN create a Th1-like environment.

The Interferon‐α/β Responses of Mice to Herpes Simplex Virus Studied at the Blood and Tissue Level In Vitro and In Vivo

Murine mononuclear leucocytes from bone marrow, spleen, lymph node and blood stimulated in vitro by UV-irradiated herpes simplex type I virus (HSV) produced about equal proportions of IFN-alpha and -beta determined by immunoassay. Thymocytes produced only IFN-alpha. The frequency of IFN-alpha/beta mRNA containing cells detected by in situ hybridization was highest with bone marrow (15 per 10(4) cells), followed by spleen (4/10(4)), lymph node (2/10(4)), blood (1/10(4)) and thymus (0.2/10(4)). Such IFN-alpha/beta producing cells (IPCs) were heavily labelled in autoradiographs, each producing about 0.4 U of IFN. After one intravenous injection of UV-irradiated HSV in mice, high levels of IFN-alpha and -beta were present in blood at 3-9h and little or none at 24h or later. Frequent cells strongly positive for IFN-alpha mRNA at in situ hybridization and for IFN-alpha/beta at immunohistochemical staining were found almost exclusively in the marginal zones of spleens. Occasional IPCs were detected in lymph nodes but not in bone marrow, liver and kidneys. The marginal zone IPCs may be the major source of IFN in blood, and high splenic levels of IFN-alpha/beta should have efficient antiviral and immunoregulatory functions.

Concurrence of High Levels of Interferons α and β in Cord and Maternal Blood and Simultaneous Presence of Interferon in Trophoblast in an African Population

A high concentration of interferon-alpha (IFN-alpha) (> 5 U/ml) in cord blood was used as the criterion for establishing our study group. In a collection from deliveries by 269 Kenyan women, 16 such cord samples with matching maternal blood and placental biopsies were identified. These 16 were studied in detail together with 23 randomly selected among those with low cord IFN-alpha levels. The levels of IFN- in retal blood correlated with levels in their mothers for both IFN-alpha and beta but not for IFN-gamma. IFN-alpha was furthermore demonstrated in villous and decidual trophoblast from 15 (94%) placentae from donors with high IFN-alpha in the cord blood but not in the placenta of any low IFN level donors. In contrast, IFN-beta was not demonstrated in any placenta. These observations suggest simultaneous IFN induction in the three compartments, transplacental IFN transport, or trophoblast production of IFN to both circulations. Looking for IFN inducers, we did serologic tests for nonspecific indicators of inflammation and for specific virus and protozoan infections, but these showed no relation to elevated IFN levels. Immunohistology also revealed no evidence of a number of placental infections. The cause of the high levels of IFN-alpha could still be infectious but remains unexplained and may be noninfectious.

Expression of alpha/beta interferons (IFN-alpha/beta) and their relationship to IFN-alpha/beta-induced genes in lymphocytic choriomeningitis.

Expression of alpha interferon (IFN-alpha)-, IFN-beta-, and IFN-alpha/beta-induced genes was monitored during the development of lymphocytic choriomeningitis (LCM) to assess whether a restricted influence of these antiviral cytokines could be found in the central nervous system (CNS). High levels of IFN-alpha (83 +/- 42 U/ml) were present in the blood of LCM virus-infected mice 3 days postinfection, whereas IFN-beta was not detected (< 1.0 U/ml) at any time point. Spleens contained high levels of IFN-alpha and IFN-beta mRNAs at days 1 and 3 postinfection, whereas no IFN-alpha mRNA and only low levels of IFN-beta mRNA were detected in brains. In situ hybridization showed IFN-alpha mRNA-expressing cells in the marginal zones of the spleen and in the subcapsular sinus and outer cortex of cervical lymph nodes. The expression of 2',5'-oligoadenylate synthetase (2',5'-OAS) mRNA followed the expression of IFN-beta mRNA in the brain, whereas 2',5'-OAS mRNA in the periphery was associated with systemic IFN-alpha. The localization of IFN-alpha-expressing cells in the spleen and lymph nodes in proximity to T- and B-cell compartments is consistent with a role for these cytokines in immune regulation. Furthermore, the absence of IFN-alpha and the relatively low level and delayed expression of IFN-beta in the brain suggest that the CNS is an especially vulnerable organ for virus replication. With certain strains of LCM virus, the absence of early antiviral IFN-alpha/beta activity and preferential virus growth in the brain might lead to targeted T-cell inflammation of the CNS, resulting in death of the animal.

Induction of IFN-alpha by HIV-1 in monocyte-enriched PBMC requires gp120-CD4 interaction but not virus replication.

IFN-alpha is in plasma of HIV-1 infected patients during early and late-stage disease and may play a role in control of virus replication. The stimulus for IFN-alpha production, the cells that produce this cytokine, and the effectiveness of this IFN-alpha response for control of virus infection are not yet defined. Culture fluids from freshly isolated PBMC of HIV-1 seronegative donors contained high levels of IFN-alpha after exposure to 100 to 1000 infectious HIV-1 particles per culture. Levels of IFN-alpha induced by HIV-1 were directly dependent on the number of monocytes in cell preparations: No IFN-alpha was detected from T cell-enriched PBMC. In monocyte cultures, induction of IFN-alpha by HIV-1 was relatively specific: Levels of IL-1 beta, IL-6, IFN-gamma, and TNF-alpha remained at baseline. Capacity of HIV-1 virions to induce IFN-alpha was not dependent on virus replication. IFN-alpha was induced by (a) heat-inactivated HIV-1, (b) virions from 8E5 cells, a cell line that releases noninfectious HIV-1, (c) HIV-1-infected cells fixed in paraformaldehyde, and (d) T cell-tropic HIV-1 that binds to but does not infect monocytes. Capacity of HIV-1 virions and HIV-1 infected cells to induce IFN-alpha was completely inhibited by soluble rCD4 or mAb against CD4 or gp120. Antibodies against CD4, however, did not induce monocytes to produce IFN-alpha. HIV-1-induced IFN-alpha production was inhibited by antibodies against both V3 loop determinants and the CD4 binding site of gp120. Further, sera and purified immunoglobulin from HIV-1 infected patients also inhibited HIV-1-induced IFN-alpha production. These observations suggest that potentially protective antiviral responses associated with IFN-alpha production in HIV-1 infected patients are inhibited by the development of antibodies against gp120.

High Levels of Interferon Alpha in the Sera of Children with Dengue Virus Infection

We measured the levels of interferon alpha (IFN alpha) in the sera of Thai children hospitalized with dengue hemorrhagic fever (DHF) or dengue fever (DF) to examine the role of IFN alpha in dengue virus infections of humans. The percentage of patients who had detectable levels of IFN alpha (> or = 3 U/ml) was higher in patients with DHF (80%, P < 0.001) and in patients with DF (60%, P < 0.001) than in healthy Thai children (7%). The levels of IFN alpha were higher in patients with DHF and in patients with DF on the first few days after the onset of fever than in healthy Thai children. The average levels of IFN alpha in patients with DHF were high two days before defervescence, decreasing gradually until the day of defervescence. There was a subset of patients with DHF who had increasing levels of IFN alpha after defervescence. However, the levels of IFN alpha in patients with DF were not high after fever subsided. The levels of IFN alpha were not different among children with DHF grades 1, 2 and 3. Among patients with DHF, T lymphocytes were activated to a higher degree in high IFN alpha producers than in low IFN alpha producers. These results indicate that similarly high levels of IFN alpha are produced in vivo during the acute stages of DHF and DF, and that high levels of IFN alpha remain after fever subsides in some patients with DHF, but not in patients with DF.

Regulation of Cytokine and Viral Gene Expression in Monocytes Infected with the Human Immunodeficiency Virus

Monocytes treated with interferon-alpha (IFN-alpha) at virus challenge show no evidence of human immunodeficiency virus (HIV) infection: no p24 antigen or reverse transcriptase (RT) activity, no viral mRNA and no proviral DNA. Levels of p24 antigen and RT activity in monocytes infected with HIV 1-3 weeks before IFN-alpha treatment gradually decrease to baseline. HIV-induced cytopathic changes are markedly reduced, as are levels of HIV mRNA: the frequency of productively infected cells is less than or equal to 1%. But, levels of proviral DNA in the IFN-alpha-treated and control HIV-infected cells are indistinguishable, and remain so through 3 weeks. Large quantities of proviral DNA in IFN-alpha-treated cells with little active transcription suggest true microbiological latency. The major potential source for IFN-alpha in HIV-infected patients is the macrophage. With any of 15 virus isolates, tumor necrosis factor-alpha, interleukin-1 beta, interleukin-6, IFN-omega or IFN-beta are not detected nor the mRNA expressed in HIV-infected or uninfected monocytes. Both uninfected and HIV-infected monocytes produce high levels of these cytokines after treatment with synthetic double-stranded RNA (poly-I:C). Uninfected monocytes also produce high levels of IFN-alpha after treatment with Poly-I:C, Newcastle disease virus or herpes simplex virus. In marked contrast, HIV-infected monocytes express no IFN-alpha activity or mRNA before or after treatment with any of these agents. The markedly diminished capacity of HIV-infected monocyte to produce IFN-alpha reflects a specific transcriptional block and may be an adaptive mechanism of virus to alter basic microbicidal functions of this cell.(ABSTRACT TRUNCATED AT 250 WORDS)

A selective defect of interferon alpha production in human immunodeficiency virus-infected monocytes.

Interferon alpha (IFN-alpha) induces significant antiretroviral activities that affect the ability of human immunodeficiency virus (HIV) to infect and replicate in its principal target cells, CD4+ T cells and macrophages. A major endogenous source of IFN-alpha during any infection is the macrophage. Thus, macrophages have the potential to produce both IFN-alpha and HIV. In this study, we examined the production of IFN-alpha and other cytokines by macrophage colony-stimulating factor (M-CSF)-treated cultured monocytes during HIV infection. Tumor necrosis factor alpha (TNF-alpha), interleukin 1 beta (IL-1 beta), IL-6, IFN-omega, or IFN-beta were not detected nor was the mRNA expressed in either uninfected or HIV-infected monocytes. However, both uninfected and HIV-infected monocytes produced high levels of each of these cytokines after treatment with synthetic double-stranded RNA [poly(I).poly(C)]. Uninfected monocytes also produced high levels of IFN-alpha after treatment with poly(I).poly(C), Newcastle disease virus, or herpes simplex virus. In marked contrast to the preceding observations, HIV-infected monocytes produced little or no IFN-alpha before or after treatment with any of these agents. The absence of detectable IFN-alpha activity and mRNA in poly(I).poly(C)-treated HIV-infected monocytes was coincident with high levels of 2',5' oligoadenylate synthetase and complete ablation of HIV gene expression. The antiviral activity induced by poly(I).poly(C) may be a direct effect of this synthetic double-stranded RNA or secondary to the low levels of IFN-beta and IFN-omega produced by infected cells. The markedly diminished capacity of HIV-infected monocytes to produce IFN-alpha may reflect a specific adaptive mechanism of virus to alter basic microbicidal functions of this cell. The inevitable result of this HIV-induced cytokine dysregulation is virus replication and persistence in mononuclear phagocytes.