Pronounced antiviral activity of human interferon on bovine and porcine cells

Juvenile Neuropsychiatric Systemic Lupus Erythematosus: Identification of Novel Central Neuroinflammation Biomarkers

INTRODUCTION

Juvenile systemic lupus erythematosus (j-SLE) is a rare chronic autoimmune disease affecting multiple organs. Ranging from minor features, such as headache or mild cognitive impairment, to serious and life-threatening presentations, j-neuropsychiatric SLE (j-NPSLE) is a therapeutic challenge. Thus, the diagnosis of NPSLE remains difficult, especially in pediatrics, with no specific biomarker of the disease yet validated.

OBJECTIVES

To identify central nervous system (CNS) disease biomarkers of j-NPSLE.

METHODS

A 5-year retrospective tertiary reference monocentric j-SLE study. A combination of standardized diagnostic criteria and multidisciplinary pediatric clinical expertise was combined to attribute NP involvement in the context of j-SLE. Neopterin and interferon-alpha (IFN-α) protein levels in cerebrospinal fluid (CSF) were assessed, together with routine biological and radiological investigations.

RESULTS

Among 51 patients with j-SLE included, 39% presented with j-NPSLE. J-NPSLE was diagnosed at onset of j-SLE in 65% of patients. No specific routine biological or radiological marker of j-NPSLE was identified. However, CSF neopterin levels were significantly higher in active j-NPSLE with CNS involvement than in j-SLE alone (p = 0.0008). Neopterin and IFN-α protein levels in CSF were significantly higher at diagnosis of j-NPSLE with CNS involvement than after resolution of NP features (respectively p = 0.0015 and p = 0.0010) upon immunosuppressive treatment in all patients tested (n = 10). Both biomarkers correlated strongly with each other (R_s = 0.832, p < 0.0001, n = 23 paired samples).

CONCLUSION

CSF IFN-α and neopterin constitute promising biomarkers useful in the diagnosis and monitoring of activity in j-NPSLE.

Lower disease activity but higher risk of severe COVID-19 and herpes zoster in patients with systemic lupus erythematosus with pre-existing autoantibodies neutralising IFN-α

OBJECTIVES

Type-I interferons (IFNs-I) have potent antiviral effects. IFNs-I are also overproduced in patients with systemic lupus erythematosus (SLE). Autoantibodies (AAbs) neutralising IFN-α, IFN-β and/or IFN-ω subtypes are strong determinants of hypoxemic COVID-19 pneumonia, but their impact on inflammation remains unknown.

METHODS

We retrospectively analysed a monocentric longitudinal cohort of 609 patients with SLE. Serum AAbs against IFN-α were quantified by ELISA and functionally assessed by abolishment of Madin-Darby bovine kidney cell protection by IFN-α2 against vesicular stomatitis virus challenge. Serum-neutralising activity against IFN-α2, IFN-β and IFN-ω was also determined with a reporter luciferase activity assay. SARS-CoV-2 antibody responses were measured against wild-type spike antigen, while serum-neutralising activity was assessed against the SARS-CoV-2 historical strain and variants of concerns.

RESULTS

Neutralising and non-neutralising anti-IFN-α antibodies are present at a frequency of 3.3% and 8.4%, respectively, in individuals with SLE. AAbs neutralising IFN-α, unlike non-neutralising AAbs, are associated with reduced IFN-α serum levels and a reduced likelihood to develop active disease. However, they predispose patients to an increased risk of herpes zoster and severe COVID-19 pneumonia. Severe COVID-19 pneumonia in patients with SLE is mostly associated with combined neutralisation of different IFNs-I. Finally, anti-IFN-α AAbs do not interfere with COVID-19 vaccine humoral immunogenicity.

CONCLUSION

The production of non-neutralising and neutralising anti-IFN-I antibodies in SLE is likely to be a consequence of SLE-associated high IFN-I serum levels, with a beneficial effect on disease activity, yet a greater viral risk. This finding reinforces the recommendations for vaccination against SARS-CoV-2 in SLE.

Neuroinflammatory Disease following Severe Acute Respiratory Syndrome Coronavirus 2 Infection in Children

OBJECTIVE

To describe neurologic, radiologic and laboratory features in children with central nervous system (CNS) inflammatory disease complicating severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.

STUDY DESIGN

We focused on CNS inflammatory diseases in children referred from 12 hospitals in the Paris area to Necker-Sick Children Reference Centre.

RESULTS

We identified 19 children who had a history of SARS-CoV-2 infection and manifest a variety of CNS inflammatory diseases: encephalopathy, cerebellar ataxia, acute disseminated encephalomyelitis, neuromyelitis optica spectrum disorder, or optic neuritis. All patients had a history of SARS-CoV-2 exposure, and all tested positive for circulating antibodies against SARS-CoV-2. At the onset of the neurologic disease, SARS-CoV-2 PCR results (nasopharyngeal swabs) were positive in 8 children. Cerebrospinal fluid was abnormal in 58% (11/19) and magnetic resonance imaging was abnormal in 74% (14/19). We identified an autoantibody co-trigger in 4 children (myelin-oligodendrocyte and aquaporin 4 antibodies), representing 21% of the cases. No autoantibody was found in the 6 children whose CNS inflammation was accompanied by a multisystem inflammatory syndrome in children. Overall, 89% of patients (17/19) received anti-inflammatory treatment, primarily high-pulse methylprednisolone. All patients had a complete long-term recovery and, to date, no patient with autoantibodies presented with a relapse.

CONCLUSIONS

SARS2-CoV-2 represents a new trigger of postinfectious CNS inflammatory diseases in children.

Monitoring Disease Activity in Systemic Lupus Erythematosus With Single-Molecule Array Digital Enzyme-Linked Immunosorbent Assay Quantification of Serum Interferon-α

OBJECTIVE

No simple or standardized assay is available to quantify interferon-α (IFNα) in routine clinical practice. Single-molecule array (Simoa) digital enzyme-linked immunosorbent assay (ELISA) technology enables direct IFNα quantification at attomolar (femtogram per milliliter [fg/ml]) concentrations. This study was undertaken to assess IFNα digital ELISA diagnostic performances to monitor systemic lupus erythematosus (SLE) activity.

METHODS

IFNα concentrations in serum samples from 150 consecutive SLE patients in a cross-sectional study were determined with digital ELISA and a functional biologic activity assay (bioassay). According to their Safety of Estrogens in Lupus Erythematosus National Assessment version of the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) flare composite scores, patients were divided into groups with inactive SLE (SLEDAI score of <4 or clinical SLEDAI score of 0) or active SLE (SLEDAI score of ≥4 or clinical SLEDAI score of >0), and into groups with no flare or mild/moderate flare or severe flare.

RESULTS

Based on serum samples from healthy blood donors, the abnormal serum IFNα level threshold value was 136 fg/ml. Next, using receiver operating characteristic curves for an SLE patient series that was widely heterogeneous in terms of disease activity and organ involvement, the threshold IFNα value associated with active disease was determined to be 266 fg/ml. The digital ELISA-assessed serum IFNα level was a better biomarker of disease activity than the Farr assay because its specificity, likelihood ratio for positive results, and positive predictive value better discerned active SLE or flare from inactive disease. The digital ELISA was more sensitive than the bioassay for detecting low-abnormal serum IFNα concentrations and identifying patients with low disease activity.

CONCLUSION

Direct serum IFNα determination with a highly sensitive assay might improve monitoring of clinical SLE activity and selection of the best candidates for anti-IFNα treatment.

Oncolytic Recombinant Vesicular Stomatitis Virus (VSV) Is Nonpathogenic and Nontransmissible in Pigs, a Natural Host of VSV

Vesicular stomatitis virus (VSV) is a negative-stranded RNA virus that naturally causes disease in livestock including horses, cattle and pigs. The two main identified VSV serotypes are New Jersey (VSNJV) and Indiana (VSIV). VSV is a rapidly replicating, potently immunogenic virus that has been engineered to develop novel oncolytic therapies for cancer treatment. Swine are a natural host for VSV and provide a relevant and well-established model, amenable to biological sampling to monitor virus shedding and neutralizing antibodies. Previous reports have documented the pathogenicity and transmissibility of wild-type isolates and recombinant strains of VSIV and VSNJV using the swine model. Oncolytic VSV engineered to express interferon-beta (IFNβ) and the sodium iodide symporter (NIS), VSV-IFNβ-NIS, has been shown to be a potent new therapeutic agent inducing rapid and durable tumor remission following systemic therapy in preclinical mouse models. VSV-IFNβ-NIS is currently undergoing clinical evaluation for the treatment of advanced cancer in human and canine patients. To support clinical studies and comprehensively assess the risk of transmission to susceptible species, we tested the pathogenicity and transmissibility of oncolytic VSV-IFNβ-NIS using the swine model. Following previously established protocols to evaluate VSV pathogenicity, intradermal inoculation with 10⁷ TCID₅₀ VSV-IFNβ-NIS caused no observable symptoms in pigs. There was no detectable shedding of infectious virus in VSV-IFNβ-NIS in biological excreta of inoculated pigs or exposed naive pigs kept in direct contact throughout the experiment. VSV-IFNβ-NIS inoculated pigs became seropositive for VSV antibodies, while contact pigs displayed no symptoms of VSV infection, and importantly did not seroconvert. These data indicate that oncolytic VSV is both nonpathogenic and not transmissible in pigs, a natural host. These findings support further clinical development of oncolytic VSV-IFNβ-NIS as a safe therapeutic for human and canine cancer.

Cross-species antiviral activity of goose interferon lambda against duck plague virus is related to its positive self-regulatory feedback loop

Duck plague virus (DPV) is a virus of the Herpesviridae family that leads to acute disease with a high mortality rate in ducks. Control of the disease contributes to the development of poultry breeding. Type III IFN family (IFN-λs) is a novel member of the IFN family, and goose IFN-λ (goIFN-λ) is a newly identified gene whose antiviral function has only been investigated to a limited extent. Here, the cross-species antiviral activity of goIFN-λ against DPV in duck embryo fibroblasts (DEFs) was studied. We found that pre-treatment with goIFN-λ greatly increased the expression of IFN-λ in both heterologous DEFs and homologous goose embryo fibroblasts (GEFs), while differentially inducing IFNα- and IFN-stimulated genes. Additionally, a positive self-regulatory feedback loop of goIFN-λ was blocked by a mouse anti-goIFN-λ polyclonal antibody, which was confirmed in both homologous GEFs and goose peripheral blood mononuclear cells (PBMCs). The suppression of the BAC-DPV-EGFP by goIFN-λ in DEFs was confirmed by fluorescence microscopy, flow cytometry (FCM) analysis, viral copies and titre detection, which can be rescued by mouse anti-goIFN-λ polyclonal antibody incubation. Finally, reporter gene assays indicated that the cross-species antiviral activity of goIFN-λ against BAC-DPV-EGFP is related to its positive self-regulatory feedback loop and subsequent ISG induction. Our data shed light on the fundamental mechanisms of goIFN-λ antiviral function in vitro and extend the considerable range of therapeutic applications in multiple-poultry disease.

Cross-Species Antiviral Activity of Goose Interferons against Duck Plague Virus Is Related to Its Positive Self-Feedback Regulation and Subsequent Interferon Stimulated Genes Induction

Interferons are a group of antiviral cytokines acting as the first line of defense in the antiviral immunity. Here, we describe the antiviral activity of goose type I interferon (IFNα) and type II interferon (IFNγ) against duck plague virus (DPV). Recombinant goose IFNα and IFNγ proteins of approximately 20 kDa and 18 kDa, respectively, were expressed. Following DPV-enhanced green fluorescent protein (EGFP) infection of duck embryo fibroblast cells (DEFs) with IFNα and IFNγ pre-treatment, the number of viral gene copies decreased more than 100-fold, with viral titers dropping approximately 100-fold. Compared to the control, DPV-EGFP cell positivity was decreased by goose IFNα and IFNγ at 36 hpi (3.89%; 0.79%) and 48 hpi (17.05%; 5.58%). In accordance with interferon-stimulated genes being the “workhorse” of IFN activity, the expression of duck myxovirus resistance (Mx) and oligoadenylate synthetases-like (OASL) was significantly upregulated (p < 0.001) by IFN treatment for 24 h. Interestingly, duck cells and goose cells showed a similar trend of increased ISG expression after goose IFNα and IFNγ pretreatment. Another interesting observation is that the positive feedback regulation of type I IFN and type II IFN by goose IFNα and IFNγ was confirmed in waterfowl for the first time. These results suggest that the antiviral activities of goose IFNα and IFNγ can likely be attributed to the potency with which downstream genes are induced by interferon. These findings will contribute to our understanding of the functional significance of the interferon antiviral system in aquatic birds and to the development of interferon-based prophylactic and therapeutic approaches against viral disease.

Low-dose oral interferon modulates expression of inflammatory and autoimmune genes in cattle

While the safety and efficacy profiles of orally administered bovine interferon (IFN) alpha have been documented, the mechanism(s) that result in clinical benefits remain elusive. One approach to delineating the molecular pathways of IFN efficacy is through the use of gene expression profiling technologies. In this proof-of-concept study, different (0, 50, 200 and 800 units) oral doses of natural bovine IFN (type I) were tested in cattle to determine if oral IFN altered the expression of genes that may be pivotal to the development of systemic resistance to viral infections such as foot-and-mouth disease (FMD). Oral IFN was administered twice: Time 0 and 8h later. Blood was collected at 0, 8 and 24h after the first IFN administration, and DNA isolated from peripheral blood mononuclear cells (PBMCs) was employed in quantitative polymerase chain reaction (qPCR) microarray assays. Within 8h, 50 and 200 units of oral IFN induced significant (P<0.05) changes in expression of 41 of 92 tested autoimmune and inflammatory response-associated genes. These data suggest that orally administered IFN is a viable approach for providing short-term antiviral immunity to livestock exposed to viruses such as FMD virus (FMDV) until such a time that an effective vaccine can be produced and distributed to producers.

Characterization of bovine interferon α1: expression in yeast Pichia pastoris, biological activities, and physicochemical characteristics

A bovine interferon α (BoIFNα) gene that included signal sequence was amplified from bovine liver genomic DNA. The gene was named BoIFN-α1 according to the position at which the encoded gene of the bovine IFN was located in the bovine genome. The sequence included a 23-amino-acid signal peptide and a 166-amino-acid mature peptide. The structural characteristics and phylogenetic relationships of the BoIFN-α1 gene were analyzed. A recombinant mature BoIFN-α1 (rBoIFN-α1) was expressed in the yeast Pichia pastoris. Physicochemical characteristics and antiviral activity were determined in vitro. Recombinant BoIFN-α1 was found to be highly sensitive to trypsin and stable at pH 2.0 or 65°C. It also exhibited antiviral activity, which was neutralized by a rabbit anti-rBoIFNα polyclonal antibody. This study revealed that rBoIFN-α1 has the typical characteristics of IFNα and can be used for both research and industrial application.

Assessment of interferon-related biomarkers in Aicardi-Goutières syndrome associated with mutations in TREX1, RNASEH2A, RNASEH2B, RNASEH2C, SAMHD1, and ADAR: a case-control study

BACKGROUND

Aicardi-Goutières syndrome (AGS) is an inflammatory disorder caused by mutations in any of six genes (TREX1, RNASEH2A, RNASEH2B, RNASEH2C, SAMHD1, and ADAR). The disease is severe and effective treatments are urgently needed. We investigated the status of interferon-related biomarkers in patients with AGS with a view to future use in diagnosis and clinical trials.

METHODS

In this case-control study, samples were collected prospectively from patients with mutation-proven AGS. The expression of six interferon-stimulated genes (ISGs) was measured by quantitative PCR, and the median fold change, when compared with the median of healthy controls, was used to create an interferon score for each patient. Scores higher than the mean of controls plus two SD (>2·466) were designated as positive. Additionally, we collated historical data for interferon activity, measured with a viral cytopathic assay, in CSF and serum from mutation-positive patients with AGS. We also undertook neutralisation assays of interferon activity in serum, and looked for the presence of autoantibodies against a panel of interferon proteins.

FINDINGS

74 (90%) of 82 patients had a positive interferon score (median 12·90, IQR 6·14-20·41) compared with two (7%) of 29 controls (median 0·93, IQR 0·57-1·30). Of the eight patients with a negative interferon score, seven had mutations in RNASEH2B (seven [27%] of all 26 patients with mutations in this gene). Repeat sampling in 16 patients was consistent for the presence or absence of an interferon signature on 39 of 41 occasions. Interferon activity (tested in 147 patients) was negatively correlated with age (CSF, r=-0·604; serum, r=-0·289), and was higher in CSF than in serum in 104 of 136 paired samples. Neutralisation assays suggested that measurable antiviral activity was related to interferon α production. We did not record significantly increased concentrations of autoantibodies to interferon subtypes in patients with AGS, or an association between the presence of autoantibodies and interferon score or serum interferon activity.

INTERPRETATION

AGS is consistently associated with an interferon signature, which is apparently sustained over time and can thus be used to differentiate patients with AGS from controls. If future studies show that interferon status is a reactive biomarker, the measurement of an interferon score might prove useful in the assessment of treatment efficacy in clinical trials.

FUNDING

European Union's Seventh Framework Programme; European Research Council.

Hemagglutinin-dependent tropism of H5N1 avian influenza virus for human endothelial cells

Although current H5N1 highly pathogenic avian influenza viruses (HPAIV) are inefficiently transmitted to humans, infected individuals can suffer from severe disease, often progressing rapidly to acute respiratory distress syndrome and multiorgan failure. This is in contrast with the situation with human influenza viruses, which in immunocompetent individuals usually cause only a respiratory disease which is less aggressive than that observed with avian H5N1 viruses. While the biological basis of inefficient transmission is well documented, the mechanisms by which the H5N1 viruses cause fatal disease remain unclear. In the present study, we demonstrate that human pulmonary microvascular endothelial cells (hPMEC) had a clearly higher susceptibility to infection by H5N1 HPAIV than to infection by human influenza viruses. This was measurable by de novo intracellular nucleoprotein production and virus replication. It was also related to a relatively higher binding capacity to cellular receptors. After infection of hPMEC, cell activation markers E-selectin and P-selectin were upregulated, and the proinflammatory cytokines interleukin-6 and beta interferon were secreted. H5N1 virus infection was also associated with an elevated rate of cell death. Reverse genetics analyses demonstrated a major role for the viral hemagglutinin in this cell tropism. Overall, avian H5N1 viruses have a particular receptor specificity targeting endothelial cells that is different from human influenza viruses, and this H5N1 receptor specificity could contribute to disease pathogenesis.

Production d’interféron alpha dans le sérum des très jeunes nourrissons lors d’infections virales

IFN-alpha detection is useful in some clinical circumstances, but its use has never been validated in young infants with viral infections.

OBJECTIVE

The authors wanted to determine it there was any difference in the assessment of IFN-alpha production between infants under or over six months of age.

PATIENTS AND METHOD

A series of 233 children with identified common viral infections who had been assessed for IFN-alpha production was retrospectively analyzed. The viral infections were enteroviral meningitis (n =103), respiratory syncytial virus infections (n =60), and rotavirus gastroenteritis (n =70). Data collected from the group of infants under six months of age (n =105) was compared to that of the older children (n =128). Qualitative and quantitative values of interferon-alpha were determined for each group.

RESULTS

Interferon-alpha was detected in very young infants (81.9% of cases) as often as in the older age group (80.3% of cases), for any of the three viral infections (P =0.3-0.63). The mean level of interferon-alpha production detected was not lower in the youngest group, and even higher in the group under six months of age with enteroviral meningitis.

CONCLUSION

Interferon-alpha detection in very young infants is efficient and may be useful to differentiate between viral and bacterial infection particularly when the etiological diagnosis appears uncertain.

Evaluation of cytotoxicity and antiviral activity of recombinant human interferon alfa-2a and recombinant human interferon alfa-B/D hybrid against bovine viral diarrhea virus, infectious bovine rhinotracheitis virus, and vesicular stomatitis virus in vitro

OBJECTIVE

To evaluate cytotoxicity and antiviral activity of recombinant human interferon alfa-2a and recombinant human interferon alfa-B/D hybrid against cytopathic and noncytopathic bovine viral diarrhea virus (BVDV), infectious bovine rhinotracheitis virus (IBRV), and vesicular stomatitis virus (VSV) in vitro.

SAMPLE POPULATION

Primary bovine testicular cells and Mardin Darby bovine kidney cells.

PROCEDURES

To evaluate cytotoxicity, cells were added to serial dilutions of each interferon. To evaluate antiviral activity of each interferon, interferons were serially diluted 1:10, and tissue culture cells were added; virus was then added at 3 time points. Prevention of viral infection by interferon was defined as failure to induce cytopathologic effect for VSV, IBRV, and cytopathic BVDV and failure to detect virus immunohistochemically for cytopathic and noncytopathic BVDV.

RESULTS

No evidence of cytotoxicity in either cell line was detected after incubation with interferon alfa-2a or interferon alfa-B/D. However, reduced growth rates of tissue culture cells were detected for each interferon when undiluted interferon was tested. Comparable and profound antiviral activities against cytopathic and noncytopathic BVDV were evident for each interferon. Interferon alfa-2a and interferon a-B/D had comparable antiviral activities against VSV. Neither interferon had antiviral activity against IBRV.

CONCLUSIONS AND CLINICAL RELEVANCE

The safety and marked in vitro antiviral activity against noncytopathic BVDV, cytopathic BVDV, and VSV suggest that interferons alfa-2a and alfa-B/D may be useful for treatment of natural disease after infection with these viruses.

Evaluation of antiviral activity and toxicity of recombinant human interferon alfa-2a in calves persistently infected with type 1 bovine viral diarrhea virus

OBJECTIVE

To evaluate antiviral activity and toxicity of recombinant human interferon alfa-2a in calves persistently infected with noncytopathic type 1 bovine viral diarrhea virus (BVDV).

ANIMALS

5 Holstein heifers, 4 to 12 months of age.

PROCEDURES

Calves persistently infected with noncytopathic type 1 BVDV were treated with recombinant human interferon alfa-2a every other day for 12 weeks. Viral loads were measured during the treatment period and compared with pre- and post-treatment values. Complete physical examinations were performed weekly, and calves were observed daily for signs of systemic illness. Complete blood counts and serum biochemical analyses were performed before, during, and after the treatment period. Because calves developed anemia during the treatment period, bone marrow biopsy specimens were collected. Antirecombinant human interferon alfa-2a antibody concentrations in serum samples obtained before, during, and after the treatment period were measured by use of an ELISA.

RESULTS

Recombinant human interferon alfa-2a had no antiviral activity against noncytopathic type 1 BVDV in persistently infected calves. All calves developed microcytic anemia during the treatment period that persisted for up to 13 weeks after cessation of treatment. Anti-interferon antibodies were detected during the treatment period and persisted for at least 2 weeks after cessation of treatment.

CONCLUSIONS AND CLINICAL RELEVANCE

Because of lack of in vivo antiviral activity against BVDV, recombinant human interferon alfa-2a has little promise as a therapeutic agent for the treatment of BVDV infection, at least in persistently infected cattle. Furthermore, treatment was associated with adverse immunologic and hematologic effects.

Reduced blood CD123+ (lymphoid) and CD11c+ (myeloid) dendritic cell numbers in primary HIV-1 infection

Successful immunologic control of HIV infection is achieved only in rare individuals. Dendritic cells (DCs) are required for specific antigen presentation to naive T lymphocytes and for antiviral, type I interferon secretion. Two major blood DC populations are found: CD11c+ (myeloid) DCs, which secrete IL-12, and CD123+ (IL-3-receptor+) DCs (lymphoid), which secrete type I interferons in response to viral stimuli. The authors have previously found a decreased proportion of blood CD11c+ DCs in chronic HIV+ patients. In this study, 26 to 57 days after infection and before treatment, CD123+ and CD11c+ DC numbers were dramatically reduced in 13 HIV+ patients compared with 13 controls (P =.0002 and P =.001, respectively). After 6 to 12 months of highly active antiretroviral therapy, DC subpopulation average numbers remained low, but CD123+ DC numbers increased again in 5 of 13 patients. A strong correlation was found between this increase and CD4 T-cell count increase (P =.0009) and plasma viral load decrease (P =.009). Reduced DC numbers may participate in the functional impairment of HIV-specific CD4+ T cells and be responsible for the low type I interferon responsiveness already known in HIV infection. The restoration of DC numbers may be predictive of immune restoration and may be a goal for immunotherapy to enhance viral control in a larger proportion of patients.

Antibody-dependent induction of type I interferons by poliovirus in human mononuclear blood cells requires the type II fcgamma receptor (CD32)

The induction of type I interferons (IFNs) in peripheral blood mononuclear cells (PBMCs) can be triggered by viral infection or exposure to viral glycoproteins. Here we show that the IFN-alpha-inducing capacity of attenuated poliovirus vaccine strains is dramatically enhanced in the presence of human polyvalent immunoglobulin G (IgG). The transcription of both IFN-alpha and IFN-beta genes was detected by RT-PCR in stimulated cells. This antibody-dependent activation of type I IFNs genes was also observed with Formalin-inactivated or UV-inactivated poliovirus, but not with empty poliovirus capsids. The ability of poliovirus-antibody complexes to induce IFN-alpha was specifically inhibited when PBMCs were preincubated with an excess of the Fc fragment of IgG. Monoclonal antibodies directed to FcgammaRII (CD32) were also inhibitory, whereas antibodies to the two other classes of Fcgamma receptors, CD16 and CD64, were not. Also, aggregation of FcgammaRII by anti-CD32 antibodies alone failed to induce IFN-alpha production. Our results suggest that induction of type I interferons by poliovirus-antibody complexes depends on CD32-mediated phagocytosis of RNA-containing viral particles. As suggested by the results of an ELISPOT analysis, only a fraction of the IFN-alpha-producing cells are able to synthesize IFN-alpha in response to poliovirus-IgG complexes.

Role of type I IFNs in the in vitro attenuation of live, temperature-sensitive vaccine strains of human respiratory syncytial virus

The contributions of type I interferons (IFNs) to the in vitro attenuation of three temperature-sensitive (Ts) subgroup A and one subgroup B deletion mutant RSV strains were evaluated. The ability of these vaccine viruses to induce IFNs at their permissive and restrictive temperatures and their sensitivity to the antiviral effects of exogenous I IFNs were tested in human lung epithelial A549 cells. Our results show that the highly attenuated and immunogenic subgroup A vaccine strain Ts1C produced higher levels of IFN-beta than its parent RSS-2 or two related strains, Ts1A and Ts1B, at their permissive temperature. Growth of RSV-infected A549 cultures at restrictive temperatures or prior UV inactivation of the virus abolished the observed induction of IFN-beta, suggesting a strict requirement of viral replication for cellular IFN induction. The enhanced induction of IFN-beta by the highly immunogenic Ts1C at permissive temperature may be an advantageous characteristic of a live intranasal vaccine candidate. The subgroup B strain RSV B1 and its mutant cp-52 (with SH and G gene deletions) both induced similar but low levels of IFN-beta. Hence the observed overattenuation of cp-52 in human infants is probably not due to enhanced IFN induction during its replication in the host. The ability of cp-52, which does not express the SH and G proteins, to induce IFN-beta levels similar to those of its parent strain suggests that these viral proteins may not have a role in the induction of IFN-beta in the host. In addition, both subgroup A and B mutants and their respective parent strains were similarly resistant to the antiviral effects of exogenous IFN-alpha or -beta. Therefore, increased sensitivity of the mutants to IFNs does not seem to contribute to their attenuation.

Therapeutic potential for orally administered type 1 interferons

Interferons (IFNs), with annual global sales valued at more than US$4 billion, have therapeutic value in the treatment of viral, neoplastic and autoimmune diseases. Parenteral administration by high-dose injection can, however, cause serious side effects. Significant improvement in the therapeutic index of IFNs could be achieved with oral administration. Using this route, dose-related side effects are not seen, and efficacy is maintained in both animal studies and human clinical trials. Oral IFN administration appears to mimic a natural innate immune response. As such, it may represent an alternative delivery strategy to make better use of these critical cytokines.

Ability of foot-and-mouth disease virus to form plaques in cell culture is associated with suppression of alpha/beta interferon

A genetic variant of foot-and-mouth disease virus lacking the leader proteinase coding region (A12-LLV2) is attenuated in both cattle and swine and, in contrast to wild-type virus (A12-IC), does not spread from the initial site of infection after aerosol exposure of bovines. We have identified secondary cells from susceptible animals, i.e., bovine, ovine, and porcine animals, in which infection with A12-LLV2, in contrast to A12-IC infection, does not produce plaques; this result indicates that this virus cannot spread from the site of initial infection to neighboring cells. Nevertheless, A12-LLV2 can infect these cells, but cytopathic effects and virus yields are significantly reduced compared to those seen with A12-IC infection. Reverse transcription-PCR analysis demonstrates that both A12-LLV2 and A12-IC induce the production of alpha/beta interferon (IFN-alpha/beta) mRNA in host cells. However, only supernatants from A12-LLV2-infected cells have significant antiviral activity. The antiviral activity in supernatants from A12-LLV2-infected embryonic bovine kidney cells is IFN-alpha/beta specific, as assayed with mouse embryonic fibroblast cells with or without IFN-alpha/beta receptors. The results obtained with cell cultures demonstrate that the ability of A12-IC to form plaques is associated with the suppression of IFN-alpha/beta expression and suggest a role for this host factor in the inability of A12-LLV2 to spread and cause disease in susceptible animals.

Oral use of interferon

Interferon-alpha (IFN-alpha) given orally has biological activity in humans and other animals. The dose providing the most benefit delivers IFN-alpha to the oral mucosa in a concentration (10(2)-10(3) IU), similar to that naturally produced in the nasal secretions during respiratory infections. In contrast, conventional IFN therapy employs parenteral doses of > 10(6) IU and, for this reason, orally administered IFN therapies have been called low-dose treatments. Efficacy in both animal disease models and human studies has been reported, and the mechanisms whereby oral administration has a systemic effect are under active study in a number of laboratories.

Anti-viral effect of interferon-alpha on bovine viral diarrhea virus

To get basic information to control persistent virus infection among domestic animals by cytokines, the antiviral activity of four natural human cytokines against bovine viral diarrhea virus (BVDV) was evaluated. Normal bovine peripheral blood mononuclear leukocytes (PBML) and fetal bovine muscular cells (FBMC) were treated with varying doses of human interferon (IFN)-alpha, IFN-gamma, tumor necrosis factor (TNF)-alpha and TNF-beta. The antiviral activity in treated cells was measured by the titration of virus infectivity in comparison with non-treated controls. IFN-alpha significantly suppressed virus growth in both PBML and FBMC. The growth of two cytopathogenic and two noncytopathogenic strains was suppressed in the presence of more than 10(3) u/ml of IFN-alpha. Addition of either TNF-alpha or TNF-beta to IFN-alpha did not potentiate the suppressive effect. IFN-alpha also suppressed the replication of BVDV in PBML from cattle persistently infected with BVDV.

Induction of interferon-alpha by glycoprotein D of herpes simplex virus: a possible role of chemokine receptors

The induction of type I interferons by most RNA viruses is initiated by virus-derived double-stranded (ds)RNA. However, retro- and DNA-viruses, which do not synthesize dsRNA, must rely on different mechanisms of induction. For human immunodeficiency virus type 1 (HIV-1), recombinant glycoproteins 120 or 160 suffice to induce interferon (IFN)-alpha in blood-derived lymphocytes [H. Ankel, M. R. Capobianchi, C. Castilletti, and F. Dianzani (1994). Virology 205, 34-43]. Here we show that for herpes simplex virus type 1 (HSV-1) recombinant glycoprotein, gD is the major inducer, whereas gB, gC, gE, gG, gI, and the complex of gH and gL are poor inducers. The recombinant extramembrane fragment of gD was sufficient to induce IFN-alpha levels comparable to that of intact virus. Like with HIV-1, induction was inhibited by a monoclonal antibody that recognizes cerebrosides and sulfatides. Furthermore, monoclonal antibodies specific for the chemokine receptors CCR3 and CXCR4 also blocked induction. We conclude that HSV-1 induces IFN-alpha by interaction of its glycoprotein gD with appropriate receptors on IFN-producing cells. Based on the known receptor roles of galactosyl cerebrosides and chemokine receptors in HIV infection, such structures on IFN-producing cells could also participate in the induction of IFN-alpha by HSV-1.

Serum alpha-interferon in lower respiratory tract infections of children

BACKGROUND

Serum alpha-interferon (IFN-alpha) concentrations are high in some children with viral meningitis and other viral infections. We have tried to assess the utility of determining serum IFN-alpha concentrations as a marker of acute viral respiratory infections.

METHODS

Measurement of IFN-alpha via a biologic assay on Madin-Darby bovine kidney cells was performed in 138 patients with lower respiratory tract infection in whom a pathogen was identified.

RESULTS

Serum IFN-alpha was detectable at the early stage of respiratory infections in the era of 59 of 75 (78.7%) of patients with a viral infection and in 4 of 63 (6.3%) of those with bacterial infection (P < 0.001). In the 4 patients with positive IFN-alpha and bacterial infection, a concomitant viral infection was found. The production of IFN-alpha is independent of age, and detectable levels are found in young infants, including the first 3 months of life, and in children with an acute viral disease.

CONCLUSION

This test could be useful in distinguishing between bacterial and viral origins in lower respiratory tract infection (the specificity was 94% and the sensitivity was 79%) and could help guide the use of antibiotics, but more rapid techniques, available in a matter of hours, are required.

The relationship between the interferon alpha response and viral burden in primary SIV infection

The interferon alpha (IFN-alpha) response of rhesus macaques was investigated during primary infection with pathogenic and attenuated simian immunodeficiency virus (SIV). IFN-alpha was detected in the serum of animals as early as day 4 after inoculation of SIVmac251, but remained barely detected in animals infected with the attenuated virus SIVmac251 delta nef. The peak of IFN-alpha secretion preceded that of antigenemia in animals infected with pathogenic virus, indicating that the IFN-alpha response did not prevent viral spread. In addition, elevated levels of IFN-alpha in the serum after the acute stage of infection was associated with persisting antigenemia. The analysis of lymph nodes (LNs) by in situ hybridization showed that, similar to the results obtained with peripheral blood, the induction of IFN-alpha in lymphoid organs was rapidly detected in animals infected with the pathogenic virus, but remained very limited in animals infected with the attenuated virus. Quantitation of the hybridization signal indicated that IFN-alpha-producing cells were numerous in the LNs of animals that had a high viral burden. Taken together, these findings indicate that the IFN-alpha response is unable to contain the initial burst of SIV replication.

Stably expressed antisense RNA to cytomegalovirus UL83 inhibits viral replication

The human cytomegalovirus (HCMV) open reading frame UL83 encodes a phosphoprotein of 64 to 68kDa (pp65) which is a major constituent of this virion and dense bodies. To determine the importance of the HCMV gene in the virus cycle, we studied HCMV replication in astrocytoma cells stably transfected with a retroviral vector carrying an antisense UL83 cDNA. Reverse transcription-PCR detected antisense RNA in the cytoplasm. The steady-state level of a 4-kb RNA containing coding sequences for pp65 was significantly reduced after infection of antisense cells. Concomitant with this, levels of expression of pp65 and pp71 (UL82) were severely reduced. Extracellular HCMV production was almost completely blocked, irrespective of the multiplicity of infection or the time after infection studied. The block occurred at an early phase, since immediate-early protein synthesis occurred normally, while several late proteins (e.g., pp150 [ppUL32] and assembly protein [UL80]) were absent or strongly inhibited. Normal replication of herpes simplex virus and of a pp65 deletion mutant of HCMV (RVAd65), lacking target sequences of antisense RNA, demonstrated the specificity of the block for wild-type HCMV in the antisense-stabilized cells and indicated that the block was not due to indirect interference with cellular genes. Our results appear to contradict those of Schmolke et al (S. Schmolke, H.F. Kern, P. Drescher, G. Jahn, and B. Plachter, J. Virol. 69:5959-5968, 1995), which show that UL83 is a nonessential gene for HCMV replication in vitro. This contradiction is discussed in light of the fact that the 4-kb mRNA, which codes for pp65 and was targeted in UL83-antisense cell lines, may be a bicistronic mRNA which also codes for pp71 (UL82). Thus, interference of expression from the genes encoding pp65 and pp71 by blocking of this putative bicistronic message leads to severe impairment of viral replication.

In vitro growth inhibition activities of recombinant feline interferon on all lines derived from canine tumours

To evaluate the anti-tumour effect of recombinant feline interferon (rFeIFN) against canine neoplastic cells, the antiproliferation and anti-colony-forming activities of rFeIFN were investigated in vitro, using four cell lines derived from canine tumours; oral acanthomatous epulis (MCA-B1), mammary benign mixed tumour (MCM-B2), squamous cell carcinoma (CSCC), and malignant melanoma (CMC-1). The rFeIFN had a dose-dependent inhibitory effect on the cell growth and colony formation of all the cell lines, although the degree of inhibition was lower than that in the feline cell lines used as a positive control, and the sensitivity of the cells to rFeIFN differed.

Atypical porcine type I interferon. Biochemical and biological characterization of the recombinant protein expressed in insect cells

A recombinant baculovirus was designed to express short porcine type I interferon (spI interferon), a novel and atypical type I interferon that was recently described as the product of a gene transcribed in pig trophoblast at the time of implantation in the uterus [Lefèvre, F. & Boulay, V.C. (1993) J. Biol. Chem. 268, 19,760-19,768]. The recombinant protein, secreted into the culture medium of Sf9 cells at 3 days post infection (60,000 IU/ml), was purified by ion-exchange and reverse-phase HPLC. N-terminal sequencing confirmed the predicted signal peptide cleavage site and therefore the size of the mature protein (149 amino acids), the shortest of all reported type I interferons. Purified spI interferon, with a specific antiviral activity using Madin-Darby bovine kidney cells of 3.7 x 10(7) IU/mg, is an N-glycosylated monomer of 19 kDa that possesses several physicochemical characteristics of interferons: (a) disulfide bonds are necessary for bioactivity; spI interferon is thermolabile, stable at pH 2, and able to renature after complete denaturation (1% 2-mercaptoethanol, 1% SDS, and 5 M urea); (b) the carbohydrate chain is not essential for bioactivity since no loss of antiviral activity is observed following complete deglycosylation. In this study, antiviral and anti-proliferation activities of spI interferon in cell culture were compared with those of other interferons, especially with porcine type 1 interferon-alpha. A major difference with porcine type 1 interferon-alpha was that spI interferon was not active on human cells in either test, and it was relatively more active on pig cells compared to bovine cells than porcine type 1 interferon-alpha. Serological cross-neutralization results obtained with anti-(spI interferon) serum confirmed that several members of interferon families are not antigenically related to spI interferon, in agreement with previous observations; this provides further evidence that spI interferon could represent a new family of type I interferon.

Comparison of the in vitro host range of recombinant met-interferon-con1, interferon-alpha 2b, and interferon-beta [corrected]

The antiviral activity of human r-metIFN-con1 was compared with that of IFN-alpha 2b and IFN-beta on a number of human, other primate, rodent, feline, and canine cell lines. Although the specific activities of r-metIFN-con1 and IFN-alpha 2b differed 10-fold, the host range was very similar. The host range of IFN-beta differed from that of r-metIFN-con1 and IFN-alpha 2b in that Vero cells were 100-fold better protected by IFN-beta and MDBK protected at a 100-fold less efficiency. In general, there were only minor differences between the host ranges of the three interferons, human and primate cells being better protected than those of other species. However, the tissue of origin of the cell appears to be more important than the species of origin in defining host range [corrected].

Antiviral activity of interferon against transmissible gastroenteritis virus in cell culture and ligated intestinal segments in neonatal pigs

Segments of jejunum in 5 to 6 days old piglets were surgically ligated, inoculated with transmissible gastroenteritis virus (TGEV) and 18 hours later the segments were fixed for histology or suspensions were prepared for plaque assay in swine testis (ST) cell cultures to determine the yield of virus. When the virulent Purdue strain of TGEV was used, villous atrophy was seen and TGEV antigen was demonstrated immunohistochemically in the villous enterocytes. The Miller M6 strain of virus produced less extensive lesions in the segments, but since it was titratable by plaque assay it was used in the subsequent yield reduction assays to determine the antiviral activity of interferon. When intestinal segments were inoculated simultaneously with either 3200 units of natural porcine interferon-alpha or up to 1000,000 units of recombinant human interferon-alpha 2 a, and TGEV, there no reductions in virus yield, although the same cytokines exerted an antiviral effect in ST cells treated in a similar way. However, virus yields were significantly reduced in intestinal segments in piglets treated parenterally with the synthetic interferon inducer polyinosinic: polycytidylic acid 6 hours before challenge of the segments with TGEV. There was also a trend for the antiviral effects of interferon induction before challenge to be augmented by the inclusion of interferon with the virus inoculum. It was concluded that interferon would be ineffective as a therapeutic for TGEV, although it might be useful prophylactically.

Experimental study of transplacental passage of alpha interferon by two assay techniques

Two methods of assaying alpha interferon (IFN-alpha) were compared during an experiment aimed at determining whether IFN-alpha crosses the human placenta. Human placentas, collected after delivery following a normal pregnancy to term, were catheterized on both sides: fetal and maternal. The IFN-alpha was introduced in known amounts in the maternal circulation and was assayed in the efferent fetal fluid. The following two detection methods were used: radioimmunoassay by competition with [125I]IFN-alpha and assay with a biological system in which IFN-alpha protected Madin-Darby bovine kidney cells from destruction by vesicular stomatitis virus. The results obtained by the two methods were in perfect agreement for the efferent fetal fluid samples. They showed the absence of placental transfer of IFN-alpha. The biological method was found to be more sensitive than radioimmunoassay for low IFN-alpha titers (< 10 IU/ml) but was less reproducible, probably owing to the use of twofold dilutions. The specificities of the two methods were similar and their practicalities were equivalent; the biological method, however, was less costly. The study illustrates the complementarity of the two methods, which were based on different principles. The agreement obtained between the two methods provides a clear confirmation of the experimental results.

Natural killer cell-mediated lysis of T cell lines chronically infected with HIV-1

The susceptibility of HIV-1-infected CD4+ T cell lines to natural killer (NK) cell-mediated lysis was examined. Non-adherent peripheral blood mononuclear cells (PBMC) of healthy adults lysed HUT cells chronically infected with the IIIB or WMJ1 strains of HIV-1 to a significantly greater extent than uninfected HUT cells. In contrast, Sup-T1 cells chronically infected with these two strains of HIV-1 were not lysed to a greater extent than uninfected Sup-T1 cells. Clone A1.25-infected Sup-T1 (A1.25/Sup-T1), derived from IIIB-infected Sup-T1 cells (IIIB/Sup-T1), were susceptible to non-adherent PBMC-mediated lysis, as were A1.25-infected HUT cells (A1.25/HUT). When non-adherent PBMC were depleted of CD16 (Leu-11b)+ NK cells by treatment with anti-Leu-11b plus C, lysis of HIV-1-infected HUT or Sup-T1 cells was reduced to low levels, indicating that the lysis was mediated by NK cells. Expression of HIV antigens on these target cells did not correlate with their susceptibility to NK cell-mediated lysis. Depletion of interferon-alpha (IFN-alpha) producing HLA-DR+ cells from non-adherent PBMC had no effect on the magnitude of NK cell-mediated lysis of IIIB or WMJ1-infected HUT cells. In contrast, lysis of A1.25/Sup-T1 or A1.25/HUT cells required the presence of HLA-DR+ cells. IFN-alpha production appeared to be required for NK cell-mediated lysis of A1.25/Sup-T1 or A1.25/HUT cells, while lysis of HUT cells infected with the WMJ1 or IIIB strains of HIV-1 was IFN-alpha independent. These results indicate considerable variability in the susceptibility of different HIV-1 infected T cell lines to NK cell-mediated lysis and suggest the existence of alternative mechanisms of activation of NK cells for lysis of HIV-1-infected T cell lines.

Effect of recombinant human interferon-alpha in vitro and in vivo on mitogen-induced lymphocyte blastogenesis in cats

The effect of recombinant human interferon-alpha (rHuIFN-alpha) in vitro and in vivo on mitogen-induced lymphocyte blastogenesis was evaluated in specific-pathogen-free cats. Pre-incubation of isolated feline peripheral blood lymphocytes (PBL) in vitro with either 10(4) or 10(3) International Units (U) of rHuIFN-alpha for 24 h significantly suppressed (P less than 0.001 and 0.01, respectively) blastogenic responses to the phytomitogens concanavalin A (Con A) and pokeweed mitogen (PWM). Lower doses of IFN (range, 10-10(-3) U/ml) neither suppressed nor enhanced mitogenesis. In the absence of phytomitogens, incubation of PBL with 10(4) - 10(2) U (P less than 0.001) or 10 U (P less than 0.05) of rHuIFN-alpha/ml resulted in a significant decrease in incorporation of [methyl-3H] thymidine into newly synthesized cellular DNA. Cultures of PBL exposed continuously for 4 days to rHuIFN-alpha doses of 10(4) U/ml or less did not demonstrate specific reductions in cell viability, indicating that the observed antiproliferative actions of IFN apparently were independent of any direct cytotoxic effects. To investigate the dose-response effects of rHuIFN-alpha in vivo on lymphocyte blastogenesis, individual groups of cats were evaluated on 3 consecutive days before and then 24 h after each cat was inoculated intramuscularly with either a high dose (10(6) U/kg), moderate dose (10(4) U/kg), or a relatively low dose (10(2) U/kg) of rHuIFN-alpha. Cats inoculated with 10(6) U of rHuIFN-alpha/kg had significantly reduced (P = 0.037) blastogenic responses to Con a at 24 h postinoculation compared to preinoculation values; mean PWM responses were also decreased, but this effect was not statistically significant. In contrast, inoculation of cats with either 10(4) or 10(2) U of rHuIFN-alpha/kg significantly enhanced (P = 0.05 or 0.008, respectively) Con A-induced blastogenesis and had no discernible effect on PWM responses. These findings suggest that very high doses of rHuIFN-alpha given parenterally may be associated with suppression of certain T-cell responses in cats; conversely, much lower doses may be immunoenhancing.

Comparison of the inhibitory effects of interferons-alpha and -gamma on testosterone production in porcine Leydig cell culture

In porcine Leydig cell culture, incubation with natural or recombinant human interferon-alpha (IFN-alpha), or recombinant porcine IFN-gamma preparations were effective in inhibiting basal and human chorionic gonadotropin (hCG)-stimulated testosterone production in a dose-dependent manner. Combined treatment with any of the human IFN-alpha preparations plus recombinant porcine IFN-gamma at the maximal inhibitory dose (1,000 pmoles/liter) further increased the inhibitory effect of any single IFN preparation on hCG-stimulated testosterone production. These results show that in porcine Leydig cells, both human IFN-alpha and porcine IFN-gamma are able to inhibit testosterone production and that the inhibitory action can be enhanced significantly by combined treatment with these types of IFNs. The enhancement of the inhibitory effect by combined treatment is consistent with the known presence of distinct cell membrane receptors for IFN-alpha and IFN-gamma.

Comparative observations of fever and associated clinical, haematological and blood biochemical changes after parenteral administration of poly I: poly C, interferon-alpha 2a and Escherichia coli endotoxin in goats

The present report describes a comparative study in dwarf goats on human IFN-alpha 2a (0.5 x 10(6) IU kg-1 body weight IM), poly I: poly C (an interferon inducer; 30 micrograms kg-1 b.w. IV), and Escherichia coli endotoxin (an I1-1 inducer; 0.1 micrograms kg-1 b.w. IV). Although IFNs are considered to be species specific, human IFN-alpha 2a was very potent in dwarf goats. All 3 stimuli induced the 'acute phase response'. Among the varied physiological alterations, which together produce this response, are fever and depression, inhibition of gastric function, tachycardia, a decrease in serum alkaline phosphatase activity, leukopenia, lymphopenia and neutropenia followed by neutrophilic leukocytosis, hypoferraemia and hypozincaemia. The results suggest that, apart from I1-1, IFN-alpha also seems to mediate the systemic 'acute phase response' to certain exogenous stimuli.

Intrathecal synthesis of interferon-alpha in infants with progressive familial encephalopathy

IFN-alpha was detected in cerebrospinal fluid and/or sera from 7 of 8 patients with a progressive familial encephalopathy associated with calcifications of the basal ganglia and white matter alterations. The secretion of IFN-alpha was prolonged, as shown by its presence at different times between birth and 5 years, and was not associated with IFN-gamma. Virological investigations excluded various congenital infections. In only 2 patients, high levels of Epstein-Barr virus antibodies were observed, indicating the possibility of an abnormal response to viral infection rather than a congenital infection. Further investigations are required for characterization of the recessive autosomal trait of this syndrome and its relation to the IFN system.

Effect of cloned human interferon-alpha 2a on bovine parainfluenza-3 virus. Brief report

Pretreatment of bovine turbinate (BTu) cells with cloned human interferon (IFN)-alpha 2a reduced the yield of infectious bovine parainfluenza-3 virus (PI-3 V). Intracellular synthesis of HN glycoprotein was reduced on postinfection day 1 (PID 1), but it recovered to normal levels subsequently. However, reduction of this protein persisted in the released virus through PID 2. Thin section electron microscopy demonstrated a drastically reduced release of mature virions and an accumulation of viral nucleocapsids inside the cytoplasm on PID 2. These results suggest that cloned human IFN-alpha 2a affects the glycoprotein synthesis, and morphogenesis of bovine PI-3 V, and thus inhibits the release of viral particles from treated cells.

Interferon gamma in acute and subacute encephalitis

Intrathecal synthesis of interferon gamma was shown in 14 out of 16 samples of cerebrospinal fluid collected in the first days of disease in adults, children, and newborn infants with herpes encephalitis. This synthesis was concomitant with that of interferon alpha and was switched off when the specific antibodies in the central nervous system increased. No endogenous interferon gamma was detected in 11 serum samples or 13 samples of cerebrospinal fluid collected early in the course of the disease from patients with measles encephalitis and rubella encephalitis, or in serum and cerebrospinal fluid samples from seven patients with subacute sclerosing panencephalitis. In serum collected after the 10th day after the onset of neurological symptoms interferon gamma was present at low concentrations in only three out of 11 serum specimens from patients with measles encephalitis or rubella encephalitis. Interferon gamma was present in patients with acute herpes encephalitis and there was active virus replication, but it was not present in postinfectious encephalitis. Possibly the local production of specific antibodies masks the viral antigens and switches off the induction of interferons.

Augmentation of endotoxin fever by recombinant human beta interferon in rabbits

Nonpyrogenic amounts of endotoxin (0.1 to 1 ng/kg), hardly detectable by conventional Limulus amoebocyte lysate tests, could produce a fever of around 1 degree C when injected with a nonpyrogenic dose (6 X 10(5) U/kg) of recombinant human beta interferon (IFN-beta) in rabbits. Release of endogenous IFN and tumor necrosis factor by endotoxin was also dramatically increased by recombinant human IFN-beta, and their levels in the blood were closely correlated with the increase of body temperature. These data suggest, if the synergism between IFN and endotoxin also operates in the homologous system (human IFN-human cells), that contaminating endotoxin in IFNs, even if not detectable by Limulus amoebocyte lysate test, can contribute to IFN fever to a considerable extent in humans.

Absence of detectable serum interferon in acute and chronic viral hepatitis

Amounts of interferon were measured in sera from 59 patients with acute viral hepatitis and 49 patients with chronic hepatitis B and compared to those from patients with nonviral liver disease or influenza, and from healthy controls. In all patients with acute and chronic viral hepatitis, no serum interferon could be detected, confirming data from earlier studies of acute viral hepatitis in which no circulating interferon was found. Our results disprove the view that the amounts of serum interferon, detected at the time of the acute clinical illness, may be a determinant of outcome.

Immune functions in healthy blood donors with HLA-DW2 and -DW3 antigens

We compared healthy blood donors with and without HLA-Dw2 and -Dw3 in immunity assays, the results of which have been found to be abnormal in multiple sclerosis or autoimmune diseases. Tests included lymphocyte blast transformation responses to rubella, mumps and purified tuberculin (PPD), in vitro production of IgG and interferons, natural killer (NK) cell function and measurement of serum antibodies to measles, rubella, mumps and herpes simplex viruses. HLA-Dw2-positive subjects had a lower lymphocyte blast transformation response to rubella virus antigen and a lower NK cell function compared with HLA-Dw2-negative subjects. The presence of HLA-Dw3 was associated with an increased spontaneous and mumps virus-induced immunoglobulin production. No significant differences were found in other assays. These results support the existence of HLA-Dw2- and Dw3-associated deviation of immune responsiveness, which may contribute to the susceptibility of multiple sclerosis or other autoimmune type diseases.

An interferon analogue, [Ala 30,32,33]HuIFN-alpha 2, acting as a HuIFN-alpha 2 antagonist on bovine cells

We have studied the biological and receptor binding properties of a human alpha 2-interferon (HuIFN-alpha 2) analogue, [Ala30,32,33] HuIFN-alpha 2, which is shown in the accompanying paper (1) to be biologically inactive on homologous cells. Here we demonstrate that this analogue is also devoid of biological activity on bovine MDBK cells. However, whereas the analogue did not inhibit the binding of radiolabeled HuIFN-alpha 2 to WISH cells, it did compete for binding to receptors on the bovine cells. This behavior suggested that [Ala30,32,33] HuIFN-alpha 2 could act as an antagonist of HuIFN-alpha 2 on bovine cells and indeed coaddition of the analogue and native HuIFN-alpha 2 to MDBK cells competitively inhibited both the antiviral and antiproliferative activity of HuIFN-alpha 2.

Early changes in immune parameters induced by an acute nonantigenic inflammation in mouse: influence of imuthiol

Calcium pyrophosphate (CaPP)-induced pleurisy, may represent one of the simplest expressions of inflammation in that the irritant is a non-diffusible, non-antigenic and non-pyrogenic agent. Spleen or lymph node T or B cell numbers and activities, as well as NK activity, were modified at distance by CaPP-pleurisy. An intense increase in blood polymorphonuclear cells was also triggered by the inflammatory process. Treatment with imuthiol (sodium diethyldithiocarbamate), an agent known to be active on the T-cell lineage, restored towards control values the inflammatory response and tended to normalize white blood cell percentages altered by the inflammatory process. The findings suggest imuthiol could be employed as a virtually nontoxic and non-steroidal anti-inflammatory agent.