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Interferon Alfa-2b or not 2b? Significant differences exist in the decision-making process between melanoma patients who accept or decline high-dose adjuvant interferon Alfa-2b treatment.

BACKGROUND: Patients with thick (Breslow>4 mm) primary melanoma and/or regional nodal metastasis have a high risk of tumor recurrence. High-dose adjuvant interferon (IFN) alfa-2b offers /=50% risk of recurrence/disease-related mortality and offered IFN. Telephone surveys delineated reasons behind patients' decisions to accept IFN. RESULTS: Acceptors, 60 of 135 (45%), decided to take IFN alfa-2b whereas 75 of 135 (55%) declined. Being female (OR, 2.4; 95% CI, 1.17-5.03; p=.017) and positive SLN status (OR, 2.2; 95% CI, 1.01-4.97; p=.048) were strongly associated with patients who chose IFN. Acceptors of IFN were younger, more influenced by physicians, and less affected by depression and side effect profile (p<.05 for all). Decliners were more concerned by strained relationships with family and social life (p<.05). CONCLUSIONS: Gender and positive SLN were predictive of high-risk melanoma patients' acceptance of IFN treatment. Physician insight into melanoma patients' therapeutic decision-making process can guide patients through this difficult disease.

Adult↗

Interferon-alpha-2B and ribavirin in combination for chronic hepatitis C patients not responding to interferon-alpha alone: an Italian multicenter, randomized, controlled, clinical study.

OBJECTIVE: The aim of the study was to assess the efficacy of interferon (IFN)-alpha-2b and ribavirin in combination in the treatment of chronic hepatitis C (CHC) patients unresponsive to a previous treatment with IFN-alpha-2b alone. METHODS: We conducted a randomized study in 303 CHC patients. One hundred fifty-two patients received subcutaneous administration of recombinant IFN-alpha-2b (3 MU thrice weekly) and ribavirin (1000-1200 mg/daily per os), whereas 151 received IFN-alpha-2b alone (6 MU thrice weekly). Both ribavirin and IFN-alpha-2b were given for 24 wk, regardless of treatment response. Alanine aminotransferase (ALT) levels and HCV RNA titer were checked during the treatment period and for a further 24 wk. RESULTS: Normal ALT levels were observed in 64.5% of the patients treated with IFN-alpha and ribavirin and in 22.6% of the patients treated with IFN-alpha alone. In the group of patients receiving IFN-alpha and ribavirin HCV RNA was not detectable in 40% of patients responders and remained undetectable in 44.2% of sustained responders. In the group of patients receiving IFN-alpha alone HCV RNA was not detectable in 24.2% of patients responders and remained not detectable in 33.3% of sustained responders. CONCLUSIONS: A 24-wk treatment course with IFN-alpha and ribavirin given to patients with a previous lack of response to IFN-alpha alone offers a chance of a sustained biochemical and virological response, at least in a subset of such patients. The role of long-term therapy in inducing prolonged remission still remains to be explored.

Adult↗

The in vitro effects of interferon-gamma, interferon-alpha, and tumour-necrosis factor-alpha on erythroid burst-forming unit growth in patients with non-leukaemic myeloproliferative disorders.

We have studied the effects of interferons gamma (IFN-gamma) and alpha (IFN-alpha), and tumour-necrosis factor-alpha (TNF) on circulating 14-day erythroid progenitor cell (BFU-E) growth in vitro from patients with non-leukaemic myeloproliferative disorders (MPD) compared with normal controls. IFN-gamma (1000 U/ml) inhibited BFU-E growth in all controls studied (mean growth +/- SE = 61% +/- 6%, n = 10). In 7 of 11 MPD studied there was no inhibition, and in some cases clear enhancement of BFU-E growth by IFN-gamma. When cultured in the presence of recombinant erythropoietin (rEpo) 1 U/ml, both IFN-alpha and TNF (at 100 and 1000 U/ml) produced a similar degree of inhibition of BFU-E growth in MPD and controls. The inhibition by 100 U/ml IFN-alpha was abrogated, partially in controls but completely in MPD, by increasing the dose of rEpo to 5 U/ml. Similarly, the increase in rEpo dose enhanced BFU-E growth in cultures with 100 U/ml TNF, but had little effect on cultures containing 1000 U/ml of either IFN-alpha or TNF. The aberrant in vitro response to IFN-gamma demonstrated in some of these patients may be of relevance to the pathophysiology of MPD. These results fail to demonstrate a differential in vitro effect for IFN-alpha on MPD BFU-E growth compared with controls and suggest that the in vitro suppression of haemopoiesis by IFN-alpha when used in MPD treatment is non-specific.

Cells, Cultured↗

Effect of fibroblast interferon and recombinant gamma interferon on zymosan-induced nitroblue tetrazolium reduction in mouse peritoneal macrophages.

Mouse peritoneal macrophages (MPM) were cultivated with a fibroblast interferon (IFN) preparation or recombinant gamma-IFN (rIFN-alpha) for 1, 24 or 48 h. The zymosan-induced reduction of nitroblue tetrazolium (NBT) in these MPM was then measured. Fibroblast IFN enhanced the NBT reducing capacity of MPM when the incubation period was 1 h. When the incubation period was extended to 48 h, a suppressed NBT reduction by fibroblast IFN treated MPM was recorded. The influence of rIFN-alpha on MPM with regard to NBT reduction was minor. Only when the MPM were treated with a moderate dose of rIFN-alpha (10 U/ml) for 48 h was an enhanced NBT reduction recorded.

Animals↗

Antagonist peptides of human interferon-alpha2b isolated from phage display library inhibit interferon induced antiviral activity.

AIM: To screen human interferon (IFN)-alpha2b antagonist peptides from a phage displayed heptapeptide library. METHODS: WISH cells and polyclonal anti-IFN-alpha2b antibodies were used to select IFN receptor-binding peptides from a phage displayed heptapeptide library. The specific binding of phage clones was examined by phage ELISA and immunohistochemistry. The specific binding activities of synthetic peptides to WISH cells were detected by competition assay. Effects of synthetic peptides to IFN-induced antiviral activity were analyzed by evaluating the cytopathic effect (CPE) using the MTT method. RESULTS: Twenty-three positive clones were obtained after seven rounds of selection. Ten clones were randomly picked from the positive clones and were sequenced. The corresponding amino acid sequences suggested 3 groups homologous to the 3 domains of IFN-alpha2b, defined by residues 24-41, 43-49, and 148-158 of IFN-alpha2b. As they presented as corresponding to IFN receptor-binding domains, AB loop and E helix, clone No 26 and 35 were chosen for further characterization and shown to bind to WISH cells. Two peptides corresponding to clone No 26 and 35, designated SP-7(SLSPGLP) and FY-7(FSAPVRY) were shown to compete with GFP-IFN-alpha2b for binding to its receptor and to inhibit the IFN-alpha2b-induced antiviral activity. CONCLUSION: Both IFN-alpha2b antagonist peptides, SP-7 and FY-7, were able to inhibit the IFN-induced antiviral activity, and could be helpful in laying the foundation for the molecular mechanism of the interaction between IFN and its receptor.

Amino Acid Sequence↗

Critical role for STAT4 activation by type 1 interferons in the interferon-gamma response to viral infection.

Interferons (IFNs) are essential for host defense. Although the antiviral effects of the type 1 IFNs IFN-alpha and IFN-beta (IFN-alpha/beta) have been established, their immunoregulatory functions, especially their ability to regulate IFN-gamma production, are poorly understood. Here we show that IFN-alpha/beta activate STAT4 directly (STAT, signal transducers and activators of transcription) and that this is required for IFN-gamma production during viral infections of mice, in concert with T cell receptor-derived signals. In contrast, STAT1 appears to negatively regulate IFN-alpha/beta induction of IFN-gamma. Thus, type 1 IFNs, in addition to interleukin-12, provide pathways for innate regulation of adaptive immunity, and their immunoregulatory functions are controlled by modulating the activity of individual STATs.

Animals↗

Susceptibility of feline herpesvirus 1 and a feline calicivirus to feline interferon and recombinant human leukocyte interferons.

Feline lung monolayer cultures were treated with either a feline interferon (IFN) or one of two recombinant human alpha-IFNs and then challenged with feline herpesvirus 1 (FHV-1), feline calicivirus (F-9 strain), or vesicular stomatitis virus. Treatment with these IFNs reduced the viral yield for each of these three viruses as compared with that of control cultures. Vesicular stomatitis virus was more sensitive to each IFN than were FHV-1 or feline calicivirus F-9.

Animals↗

Effect of dosing schedule on pharmacokinetics of alpha interferon and anti-alpha interferon neutralizing antibody in mice.

The influences of dosing time and dosing schedule on the plasma alpha interferon (IFN-alpha) concentration and the production of anti-IFN-alpha neutralizing antibodies were investigated in ICR male mice adapted to cycles of 12 h of light and 12 h of dark. In mice pretreated with IFN-alpha for 21 days, the plasma IFN-alpha concentrations were significantly lower than those in control mice (P < 0.01). The clearance of IFN-alpha and its volume of distribution obtained at steady state were significantly higher in the animals with IFN-alpha pretreatment than in the mice without IFN-alpha pretreatment. The area under the concentration-time curve and the mean residence time of IFN-alpha were significantly smaller in IFN-alpha-pretreated animals than in control animals. The plasma IFN-alpha levels (measured 2 h after dosing) were significantly lower in mice treated daily with IFN-alpha, while the anti-IFN-alpha neutralizing antibody levels (measured 24 h after dosing) were significantly increased on days 15 and 21 of treatment. Plasma IFN-alpha levels were significantly decreased in association with the production of anti-IFN-alpha neutralizing antibodies in mice treated with IFN-alpha daily at either 0900 or 2100 h. By contrast, the plasma IFN-alpha levels (measured 2 h after dosing) remained stable in mice treated with IFN-alpha at 0900 h on alternate days, while they were significantly lower after 21 days of treatment in mice treated with IFN-alpha at 2100 h on alternate days. These changes were associated with a significant increase in the levels of anti-IFN-alpha neutralizing antibodies in the latter group. The present findings suggest that an appropriate dosing schedule and/or dosing time for IFN-alpha may reduce the level of production of anti-IFN-alpha neutralizing antibodies in experimental and clinical situations.

Animals↗

Chlamydia muridarum infection elicits a beta interferon response in murine oviduct epithelial cells dependent on interferon regulatory factor 3 and TRIF.

Chlamydia trachomatis is the most common sexually transmitted bacterial infection in the United States. Utilizing cloned murine oviduct epithelial cell lines, we previously identified Toll-like receptor 2 (TLR2) as the principal epithelial pattern recognition receptor (PRR) for infection-triggered release of the acute inflammatory cytokines interleukin-6 and granulocyte-macrophage colony-stimulating factor. The infected oviduct epithelial cell lines also secreted the immunomodulatory cytokine beta interferon (IFN-beta) in a largely MyD88-independent manner. Although TLR3 was the only IFN-beta production-capable TLR expressed by the oviduct cell lines, we were not able to determine whether TLR3 was responsible for IFN-beta production because the epithelial cells were unresponsive to the TLR3 ligand poly(I-C), and small interfering RNA (siRNA) techniques were ineffective at knocking down TLR3 expression. To further investigate the potential role of TLR3 in the infected epithelial cell secretion of IFN-beta, we examined the roles of its downstream signaling molecules TRIF and IFN regulatory factor 3 (IRF-3) using a dominant-negative TRIF molecule and siRNA specific for TRIF and IRF-3. Antagonism of either IRF-3 or TRIF signaling significantly decreased IFN-beta production. These data implicate TLR3, or an unknown PRR utilizing TRIF, as the source of IFN-beta production by Chlamydia-infected oviduct epithelial cells.

Adaptor Proteins, Vesicular Transport↗

Potentiation of lymphocyte natural killing by mixtures of alpha or beta interferon with recombinant gamma interferon.

Human lymphocytes were treated with human alpha (IFN-alpha), beta (IFN-beta), or recombinant gamma (IFN-gamma) interferons separately or in combination to determine their ability to enhance natural killing against mouse L cell targets. Our results showed that recombinant IFN-gamma was approximately 50 times more active per unit of antiviral activity than either IFN-alpha or IFN-beta. Moreover, the levels of natural killing by lymphocytes treated with combinations of IFN-alpha and IFN-beta were additive, whereas combinations of recombinant IFN-gamma and IFN-alpha or recombinant IFN-gamma and IFN-beta were synergistic. The development of natural killing in lymphocytes treated with recombinant IFN-gamma did not occur more rapidly but reached higher levels (62%) than that observed with lymphocytes treated with IFN-alpha or IFN-beta (15%). The results suggest the importance of IFN-gamma and mixtures of IFN-gamma with IFN-alpha or IFN-beta in the enhancement of natural killing activity against virus infections and neoplasia.

Adjuvants, Immunologic↗

Action of different gamma interferons on mouse leukemic cells resistant to alpha and beta interferons.

Phytohemagglutinin-induced interferon-gamma (IFN-gamma) was reported to act on mouse leukemic L1210 R cells resistant to IFN-alpha and -beta. Results reported here show that these cells are also sensitive to various preparations of murine IFN-gamma derived from different sources and purified to different degrees and that lymphokines present in the preparations are not involved in the antiviral effect of IFN. In addition, IFN-gamma preparation increases concanavalin A binding to L1210 S and L1210 R cells indicating that the sensitivity of L1210 R cells to IFN-gamma is not limited to its antiviral effect.

Animals↗

Induction of alpha/beta interferon and gamma interferon in mice infected with Listeria monocytogenes during pregnancy.

Alpha/beta interferon (IFN-alpha/beta) was induced in the bloodstream of mice 48 h after intravenous infection with Listeria monocytogenes, whereas IFN-gamma was induced in the bloodstream 6 h after stimulation with specific antigen on day 5 of infection in virgin mice. In contrast, no IFN-alpha/beta or IFN-gamma was produced in the bloodstream of pregnant mice after L. monocytogenes infection. However, unusual acid-labile IFN-alpha/beta instead of IFN-gamma was produced in some of the pregnant mice in response to specific antigen. The bacterial growth in the organs of pregnant mice in the early stage of infection was normal, but resulted in the delay of T-cell-dependent elimination of bacteria from the organs of pregnant animals in the late stage, and numerous bacteria were detected in both the placenta and the fetus. The significance of the IFN system induced by L. monocytogenes infection in pregnant mice is discussed.

Animals↗

Selection of alpha/beta interferon- and gamma interferon-resistant rickettsiae by passage of Rickettsia prowazekii in L929 cells.

The ability of endogenously produced alpha/beta interferon (IFN-alpha/beta) to inhibit rickettsial growth in infected L929 cell cultures was evaluated by comparing the growth of Rickettsia prowazekii Madrid E in untreated cultures and cultures treated with anti-mouse IFN (alpha + beta) serum. The endogenously produced IFN was neutralized, and rickettsial growth was enhanced in the antiserum-treated cultures. This inhibitory effect of endogenously produced IFN-alpha/beta was used to select rickettsiae resistant to IFN-alpha/beta. Rickettsiae were screened for resistance to IFN-alpha/beta after being cultured in untreated L929 cells for several weeks to several months. Two isolates derived from R. prowazekii Madrid E and two isolates derived from plaque-purified R. prowazekii Madrid E were plaque-purified twice, grown in embryonated hen eggs, and evaluated for resistance to IFN-alpha/beta and IFN-gamma. Compared with the parental rickettsial strain, all four isolates were significantly resistant to IFN-alpha/beta and IFN-gamma. In addition, they were as resistant or more resistant to IFN-gamma when compared with two previously described IFN-gamma resistant isolates that were selected in IFN-gamma-treated L929 cells. One of the two isolates from IFN-gamma-treated L929 cells was also resistant to IFN-alpha/beta; the other isolate was similar to the parental Madrid E strain in sensitivity to IFN-alpha/beta.

Animals↗

Priming of human monocytes for enhanced lipopolysaccharide responses: expression of alpha interferon, interferon regulatory factors, and tumor necrosis factor.

Culture of human monocytes with either granulocyte-macrophage colony-stimulating factor or gamma interferon (IFN-gamma) results in a primed state, during which these cells express heightened responses to bacterial lipopolysaccharide (LPS). The production of IFN-alpha in response to LPS by human monocytes has an absolute requirement for priming. Tumor necrosis factor (TNF) expression is also greatly enhanced in primed monocytes after LPS stimulation, but unlike IFN-alpha, TNF is readily expressed in unprimed monocytes as well. In an effort to determine the molecular events associated with IFN-alpha induction in this system, freshly isolated human monocytes were primed by culture with either IFN-gamma or granulocyte-macrophage colony-stimulating factor and then treated with LPS; expression of IFN-alpha subtype 2 (IFN-alpha 2), IFN regulatory factors (IRFs), and TNF was assessed by Northern (RNA blot) analysis. IRF-1 mRNA is expressed at high levels in monocytes and is regulated by both LPS and priming cytokines, but its expression alone does not correlate with the induction of IFN-alpha 2 expression. IRF-2 mRNA is expressed in a more gradual manner following LPS stimulation, implying a possible feedback mechanism for inhibiting IFN-alpha expression. However, nuclear run-on analysis indicates that IFN-alpha 2 is not transcriptionally modulated in this system, in striking contrast to TNF, which is clearly regulated at the transcriptional level. In addition, IFN-alpha 2 mRNA accumulation is superinduced when primed monocytes are treated with LPS plus cycloheximide, while TNF mRNA is relatively unaffected. The results demonstrate that priming can affect subsequent LPS-induced gene expression at different levels in human monocytes.

Cycloheximide↗

Beta interferon is produced by Chlamydia trachomatis-infected fibroblast-like synoviocytes and inhibits gamma interferon-induced HLA-DR expression.

Infection of fibroblast-like synovial cells with Chlamydia trachomatis (serotype D strain IC Cal 8) in culture induced the secretion of beta interferon (IFN-beta). Chlamydial infection inhibited IFN-gamma-induced expression of HLA-DR antigen in the cells. Addition of IFN-beta antibody directly to infected cultures mitigated HLA-DR inhibition, suggesting involvement of produced IFN-beta.

Cells, Cultured↗

Posttranscriptional regulation of beta interferon expression in erythroid Friend cells treated with gamma interferon.

Treatment of Friend erythroleukemia cells (FLC) with gamma interferon (IFN-gamma) in the presence of anti-IFN-beta antibodies reduces the effectiveness of the antiviral state and the induction of 2'-5'-oligoadenylate synthetase activity, indicating that the antiviral activity of IFN-gamma in FLC is in part mediated by the production of IFN-beta. Accordingly, IFN-gamma induces a less pronounced antiviral state in FLC resistant to IFN-alpha/beta than in wild-type cells. Moreover, while results of run-on assays indicate that both IFN-alpha and -beta genes are constitutively transcribed in these cells, FLC treatment with IFN-gamma induces only IFN-beta mRNA accumulation. These results indicate that posttranscriptional mechanisms are involved in the regulation of IFN-beta and -alpha expression by IFN-gamma. The low amounts of the induced IFN-beta synergize with IFN-gamma in mounting the potent antiviral effect.

2',5'-Oligoadenylate Synthetase↗

Constitutive expression of an ISGF2/IRF1 transgene leads to interferon-independent activation of interferon-inducible genes and resistance to virus infection.

Interferon (IFN)-stimulated gene factor 2 (ISGF2) plays a role in transcription of the beta IFN (IFN-beta) gene and IFN-stimulated genes (ISGs) and may function as a central mediator of cytokine responses. Constitutive ISGF2 transgene expression resulted in substantial resistance to three RNA virus families. This phenotype was not a consequence of IFN production and may have arisen directly through ISG expression. ISGF2 acted generally as a positive transcription factor through binding sites from several genes, in the context of transient cotransfection. Constitutive transcription of the endogenous IFN-beta gene, and several genes that are normally induced by either IFN-alpha or IFN-gamma, or only by IFN-alpha, was elevated in cells that constitutively express an ISGF2 transgene. However, constitutive and virus-induced levels of IFN-beta mRNA were unaffected in such cell lines.

Antibodies, Viral↗

Induction of beta interferon by human immunodeficiency virus type 1 and its gp120 protein in human monocytes-macrophages: role of beta interferon in restriction of virus replication.

In vitro cultivated human monocytes show a time-dependent differentiation into macrophages, characterized by an increased expression of macrophage-specific antigens. Monocytes-macrophages were infected with human immunodeficiency virus type 1 strain Ba-L (HIV-1Ba-L) at different stages of differentiation. When 7-day cultured macrophages were infected in the presence of antibodies to beta interferon (IFN-beta), a significant increase in HIV-1 p24 release was detected. This effect was not observed in 1-day monocytes. This finding suggests that IFN-beta secreted by the infected macrophages inhibits p24 release. Treatment of cultured macrophages with recombinant gp120 (rgp120) protein resulted in the induction of IFN-beta mRNA and in an antiviral state to vesicular stomatitis virus. This rgp120-induced antiviral state was largely neutralized by antibodies to IFN-beta, whereas anti-IFN-alpha antibodies were ineffective. In cultured macrophages, 0.1 IU of IFN-beta per ml was sufficient to induce a marked inhibition of vesicular stomatitis virus yield, whereas this dose was ineffective in 1-day monocytes. These results indicate that (i) HIV-1 (possibly in part through its gp120 protein) induces low levels of IFN-beta in macrophages and (ii) this IFN-beta is very effective in inducing an antiviral state in differentiated macrophages.

Cell Differentiation↗