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P Eid

Publications and source records attributed to P Eid.

At least 19 recordsLinked to original sources
PubMed2002

Direct signal transduction via functional interferon-alphabeta receptors in CD34+ hematopoietic stem cells.

Affinity purified, freshly isolated CD34+ progenitors were shown to express low levels of type I interferon (IFN) receptors (740 +/- 60 binding sites/cell, K(d) 0.7 +/- 0.04 nM) determined by Scatchard's analysis using a radiolabelled, neutralizing, monoclonal antibody directed against the IFNAR1 chain of the human type I IFN receptor. Treatment of freshly isolated (day 0), highly purified (>95% pure) CD34+ cells with recombinant IFN-alpha resulted in rapid tyrosine phosphorylation and activation of STAT1, Tyk2 and JAK1 as shown by Western immunoblotting. Similarly, IFN treatment was shown by confocal microscopy to result in rapid nuclear localization of the transcription factors IRF1 and STAT2, demonstrating the presence of functional IFN receptors on freshly isolated (day 0) CD34+ cells. The number of specific type I IFN receptor binding sites expressed on hematopoietic progenitor cells increased to some 1440 +/- 40 per cell after 11 days of cultivation of CD34+ cells in vitrosuggesting that receptor expression increases with cell differentiation. IFN-mediated signal transduction and the inhibitory effect of IFN-alpha on 7 or 14 days CFU-GM and BFU-E colony formation was abrogated in the presence of the anti-IFNAR1 mAb, indicating that IFN-alpha acts directly on the proliferation of human hematopoietic progenitor cells via receptor activated signal transduction without excluding the induction of other cytokines or growth factors by residual accessory cells.

Active Transport, Cell Nucleus↗
PubMed2000

Regulation of chemokine/cytokine network during in vitro differentiation and HIV-1 infection of human monocytes: possible importance in the pathogenesis of AIDS.

The monocyte/macrophage lineage represents heterogeneous cell populations characterized by major differences in the phenotype and functional activities. These cells are a major source of soluble factors, such as cytokines and chemokines, which can both affect HIV replication and AIDS pathogenesis. Although monocytes/macrophages are unanimously considered important targets of HIV-1 infection, the HIV-induced alterations in their physiological functions at different stages of differentiation are still matter of debate. In this article, we review our data on the regulation of chemokine/cytokine network with regard to macrophage differentiation and HIV-1 infection, in comparison with studies from other groups. The ensemble of the results emphasizes that: 1) macrophages markedly differ with respect to monocytes for a variety of responses potentially important in the pathogenesis of HIV infection; and 2) the experimental conditions can influence the HIVmonocyte/macrophage interactions, reflecting the possible in vivo existence of a spectrum of responses among macrophage populations.

Cell Differentiation↗
PubMed2000

Localization of a receptor nonapeptide with a possible role in the binding of the type I interferons.

Interferons (IFNs) in common with other cytokines activate Janus tyrosine kinases and latent STAT transcription factors upon binding to their cell surface receptor. Type I IFNs bind to a receptor composed of two transmembrane polypeptides, IFNAR1 and IFNAR2, which belong to the class II cytokine receptor family that also includes the cellular receptors for IFN-gamma, interleukin-10 and coagulation protease factor VII (tissue factor). The extracellular domain of the type I IFN receptor chain IFNAR1, has four fibronectin type-III sub-domains. Human IFNAR1 has intrinsic weak affinity for type I IFNs and plays an essential role in transmembrane signaling, formation of a high affinity complex with IFN and the modulation of ligand specificity. In order to characterise the ligand binding site on IFNAR1 we analysed the epitope recognized by the anti-IFNAR1 mAb, 64G12, which inhibits the binding and biological activities of both IFN-alpha and IFN-beta. The target peptide recognized by the 64G12 mAb was determined by screening a set of 48 overlapping peptides covering the first two subdomains (residues 23-229) of the extracellular region of IFNAR1. The results of this study show that the peptide (FSSLKLNVY), localized within the first sub-domain (residues 89-97) of IFNAR1, which is recognized by the 64G12 mAb, most likely overlaps a site to which both IFN-alpha and IFN-beta bind in the ligand-receptor complex. Thus, since the 64G12 mAb can neutralize the biological activities of all the type I IFNs tested, we suggest that the target peptide recognized by the 64G12 mAb, is a possible anchorage point on IFNAR1, common to binding of both IFN-alpha and IFN-beta.

Amino Acid Sequence↗
PubMed1999

High pressure fourier transform infrared spectroscopy of poly(dA)poly(dT), poly(dA) and poly(dT).

The effect of hydrostatic pressure upon the DNA duplex, poly(dA)poly(dT), and its component single strands, poly(dA) and poly(dT) has been studied by fourier-transform infrared spectroscopy (FT-IR). The spectral data indicate that at 28 degrees C and pressures up to 12 kbar (1200 MPa) all three polymers retain the B conformation. Pressure causes the band at 967 cm(-1), arising from water-deoxyribose interactions, to shift to higher frequencies, a result consistent with increased hydration at elevated pressures. A larger pressure-induced frequency shift in this band is observed in the single stranded polymers than in the double stranded molecule, suggesting that the effect of pressure on the hydration of single strands may be greater than upon a double stranded complex. A pressure-dependent hypochromicity in the bands attributed to base stacking indicates that pressure facilitates the base stacking in the three polymers, in agreement with previous assessments of the importance of stacking in the stabilization of DNA secondary structure at ambient and high pressures.

Journal Article↗
PubMed1999

Oromucosal interferon therapy: pharmacokinetics and pharmacodynamics.

Oromucosal administration of [125I]-labeled recombinant human interferon-alpha1-8 (IFN-alpha1-8), which is biologically active in the mouse, resulted in readily detectable levels of radioactivity in the serum of animals within 5 min. Biologically active IFN could not be detected in the serum at any time after oromucosal administration, however, and SDS-PAGE analysis showed that the material present in the serum was of low molecular weight and most probably reflected absorption of degradation products following digestion of IFN in the stomach and small intestine. Furthermore, oromucosal administration of murine IFN-alpha/beta (MuIFN-alpha/beta) had no significant effect on the expression of IFN-responsive genes in either peripheral blood mononuclear cells or splenic lymphocytes even though in the same animals IFN treatment activated gene transcription locally in the lymphoid tissue of the oropharyngeal cavity and caused a marked systemic antiviral activity. Oromucosal administration of MuIFN-alpha/beta had no significant effect on either the number of circulating peripheral blood leukocytes or the number of granulocyte-macrophage colonies recovered from the bone marrow of IFN-treated animals. These results suggest that the mechanism of action of oromucosal IFN therapy is distinct from that of parenterally administered IFN and may involve, in the abundant lymphoid or epithelial tissue of the oropharyngeal cavity, either production of a soluble factor or activation of a specific cell population that enters the circulation to mediate the elimination of virus-infected or neoplastic cells.

2',5'-Oligoadenylate Synthetase↗
PubMed1998

Prolonged allograft survival in cynomolgus monkeys treated with a monoclonal antibody to the human type I interferon receptor and low doses of cyclosporine.

A monoclonal antibody (mAb) directed against the extracellular domain of the IFNAR1 chain of the human interferon-alpha (IFN-alpha) receptor (IFN-alphaR), which inhibits activation of the Jak-Stat signal transduction pathway, administered together with a subeffective dose of cyclosporine induced prolonged survival of skin allografts in major histocompatibility complex (MHC) divergent cynomolgus monkeys. Skin biopsies from animals treated with anti-IFN-alphaR mAb and cyclosporine revealed very low levels of MHC class I and class II antigen expression and the absence of histologic signs of rejection. Monkey antibodies (IgG) to the mouse antihuman IFN-alphaR mAb were not detected in the serum of any of the animals treated with the anti-IFN-alphaR mAb either alone or together with cyclosporine. The anti-IFN-alphaR mAb abrogated activation of the Jak-Stat signal transduction pathway in IFN-treated cells. These results, which show that selective and long-lasting immunosuppression can be obtained by short-term administration of an IFN-alpha antagonist together with a subeffective dose of cyclosporine, may have important implications for the therapy of human allograft rejection.

Animals↗
PubMed1997

Comparative study of the expression of cellular proteins in uninfected and HIV infected U937 cells using two dimensional SDS polyacrylamide gel electrophoresis.

The cellular response to HIV infection was determined by analysing the expression of cellular proteins in uninfected and HIV-1 infected U937 cells using two-dimensional protein electrophoresis. HIV infected U937 cells constitute a useful model for the study of the chronic productive infection of cells of the monocyte/macrophage lineage by the human immunodeficiency virus. Our data suggest that the expression of 70 proteins is modified following HIV infection: the expression of approximately half of these proteins was found to be increased, while that of the other half was repressed. We estimate that the expression of around fifteen of these proteins was markedly changed following HIV infection. These results suggest that HIV infection results in the modified expression of approximately 0.5% of total cellular proteins. To our knowledge, this study represents the first global quantitative analysis of the cellular response to HIV infection in a model of chronic infection of cells of the monocyte-macrophage lineage.

Cell Line↗
PubMed1997

Post-translational up-regulation of the cell surface-associated alpha component of the human type I interferon receptor during differentiation of peripheral blood monocytes: role in the biological response to type I interferon.

Human peripheral blood monocytes cultured in vitro exhibit a greater sensitivity to the antiviral effect of type I interferon (IFN) compared to freshly isolated monocytes. We evaluated the effect of macrophage differentiation on the expression of type I IFN receptors (IFN-R). Binding studies with iodinated IFN-alpha 2 and Scatchard plot analysis revealed that a single class of high-affinity receptors was present in freshly isolated monocytes. Monocyte differentiation to macrophages resulted in a three- to fourfold increase in the number of cell surface receptors with no change in their affinity. Polymerase chain reaction analysis of RNA revealed that comparable levels of mRNA for the IFN-R alpha (IFNAR1) and IFNAR2 components were expressed in freshly isolated monocytes and 7-day cultured macrophages. Likewise, the levels of IFNAR1 protein remained constant over time in culture. Immunofluorescence studies revealed that IFNAR1 was localized in intracellular compartments of freshly isolated monocytes, whereas it was predominantly detected on the cell surface in 7-day cultured macrophages. The increased expression of IFN-R on the plasma membrane of cultured macrophages may, at least in part, account for the increased antiviral effect of type I IFN in these cells. These modifications represent one of the events occurring during monocyte differentiation that may play a role in the regulation of macrophage functions.

Adolescent↗
PubMed1997

Comparison of Fourier-transform infrared spectroscopic screening of exfoliated cervical cells with standard Papanicolaou screening.

To compare Fourier-transform infrared (FTIR) spectroscopy in screening cervical cytology and standard Papanicolaou (Pap) screening with colposcopic directed biopsy as a "gold standard," we prospectively gathered FTIR samples and Pap smears of all patients attending our program's colposcopy clinics, from February to October 1995. We recorded demographic data for each patient including colposcopy, cytology, treatment follow-up, and histology. Using the colposcopically directed biopsy as the gold standard, exfoliated cervical cells from 301 patients were collected to compare cytology and FTIR spectroscopy. Based on previously established criteria, we provided distinctive definitions of both negative/positive FTIR, cytology, and histology. Results of 301 cases showed 196 positive and 105 negative cytologies. The sensitivity, specificity, false-negative rate, and false-positive rate for the Pap test were 86.6, 90.5, 13.4, and 9.5%, respectively. However, FTIR results versus histology showed 215 positive and 86 negative with a sensitivity of 98.6% and specificity of 98.8%. False-negative and false-positive rates were 1.4 and 1.2%, respectively. In the 12 cervical cancers there were no false-negative FTIR results but 3 false-negative Pap smears. The positive and negative predictive values for FTIR were 99.5 and 96.5% while the Pap values were 95.9 and 72.3%. Compared to standard Pap smears, FTIR has a better false-negative rate and negative predictive value in this preliminary study. Further work, to establish the range of each of the spectral criteria for different grades of dysplasia and that among various infectious effects, needs to be conducted before applying this research tool to a population-based study.

Biopsy↗
PubMed1996

Role of the type I interferons in allograft rejection.

Type I interferons are potent immuno-modulatory cytokines that enhance expression of the major histocompatibility complex (MHC) class I antigens, T-cell cytotoxicity, and natural killer (NK) cell activity, all of which are implicated in graft rejection. A monoclonal antibody (mAb) directed against the extracellular domain of the human interferon gamma (IFN-gamma) receptor (IFN-alpha R), which inhibits both the binding and biological activity of all the type I IFNs tested, exerted a dose-dependent inhibition of the mixed lymphocyte reaction and induced permanent survival of skin allografts in MHC-divergent Cynomologus monkeys treated with a subeffective dose of cyclosporin A. Marked differences were observed in the composition of T lymphocyte subpopulations in anti-IFN-alpha R mAb-treated animals relative to the various control groups. Skin biopsies from animals treated with anti-IFN-R Mab + cyclosporin A revealed very low levels of MHC class I and class II antigen expression and the absence of histological signs of rejection, whereas skin biopsies from control animals exhibited high levels of MHC antigen expression and the histological signs of acute rejection, including a pronounced lymphocytic infiltrate, edema, and necrosis. No monkey antibodies (IgG) to the mouse anti-human IFN-alpha R mAb were detected in the serum of any of the animals treated with the anti-IFN-alpha R mAb either alone or together with cyclosporin A. Treatment of lethally irradiated Cynomologus monkeys with the anti-IFN-alpha R mAb together with a subeffective dose of cyclosporin A was also found to markedly enhance the survival of animals grafted with allogeneic bone marrow cells from donors differing in both MHC class I and class II antigens. These results show that selective and lasting immunosuppression can be obtained by the short-term administration of an IFN-alpha antagonist together with a subeffective dose of cyclosporin A, and may have important implications for the therapy of human allograft rejection.

Animals↗
PubMed1996

Use of enzyme-labelled protein G assay for the detection of anti Borrelia burgdorferi antibodies in wild animal sera.

A modified ELISA was developed for the detection of anti-Borrelia burgdorferi (Bb) IgG antibodies in wild animal sera based on an Enzyme-Labelled-protein G Assay (ELGA). Microplates were coated with an extract of Bb sensu stricto strain (SVI) as antigen. Specific antibodies of the serum samples were detected by a peroxidase-labelled-protein G. Using comparative immunodiagnosis by means of a passive hemagglutination test (HA), ELGA was tested on 82 roe-deer blood samples. A correlation was found between the two methods (r = 0.66). Good reproducibility of titers was observed by ELGA technique. A minimal cross-reactivity was discovered with Leptospira. ELGA could facilitate the recognition of specific antibodies in collections of wild animal sera.

Animals↗
PubMed1995

Characterization of a domain of a human type I interferon receptor protein involved in ligand binding.

Two monoclonal antibodies that recognize different epitopes of the extracellular domain of one of the proteins that constitute the type I interferon receptor were used to delineate the interferon binding site. Antibody 64G12 both inhibits the binding of radiolabeled interferon-alpha 2 and IFN-alpha 8 to their cell surface receptors and neutralizes the antiviral and antiproliferative actions of all the type I interferons tested, including IFN-beta, IFN-omega, and human leukocyte IFN, a mixture of different interferon-alpha isotypes. Antibody 34F10 recognizes the type I interferon receptor with an affinity similar to that of the MAb 64G12 but does not inhibit either the binding or the biologic activity of any of the type I interferons tested. Both antibodies recognize a protein of 105 +/- 5 kD from either Daudi or Ly28 cells. Immunoprecipitation following surface iodination demonstrated that the neutralizing MAb recognizes a protein of 105 kD and the nonneutralizing MAb a protein of 110 kD in extracts of Daudi cells. A second less intense band was also detected by both antibodies. Cross-linking of IFN-alpha 2 to its receptor before immunoprecipitation prevented the neutralizing antibody from immunoprecipitating the receptor protein, but the nonneutralizing MAb was still able to recognize a 140 kD protein corresponding to the cross-linked interferon-receptor protein complex. Thus, an interferon binding domain appears to be localized in a region between amino acids 23 and 229 of the extracellular domain of a transmembrane protein that forms part of the type I interferon receptor complex containing the epitopes recognized by each antibody.

Antibodies, Monoclonal↗
PubMed1994

Differential tyrosine phosphorylation of the IFNAR chain of the type I interferon receptor and of an associated surface protein in response to IFN-alpha and IFN-beta.

The human interferon alpha-receptor (IFNAR gene product) is a transmembranal protein of 557 amino acids with an intracytoplasmic domain of 100 amino acids containing four tyrosines. Antibodies to a C-terminal peptide (residues 521-536) were developed which efficiently immunoprecipitate the 105 kDa IFNAR protein from detergent extracts of human cells. We show that the IFNAR protein becomes tyrosine phosphorylated within 5 min after treatment of human myeloma U266 cells with IFN-alpha 2, IFN-alpha 8 or IFN-beta. The IFNAR chain interacts with both IFN-alpha 2 and IFN-beta, as demonstrated by cross-linking. Among elements involved in signal transduction by type I IFNs, the tyrosine kinase Tyk2 but not Jak1, and the ISGF3 transcription factor subunit Stat2 (p113) but not Stat1 (p91), are found associated with the IFNAR protein. After IFN-beta treatment for 5 min, a tyrosine-phosphorylated protein of approximately 95 kDa (beta-PTyr) is found bound to IFNAR, but can be dissociated by denaturation. The beta-PTyr protein is present on the cell surface, like IFNAR, as shown by extracellular biotin tagging. The ratio of beta-PTyr to IFNAR tyrosine phosphorylation is much higher with IFN-beta than with IFN-alpha 2 or 8. Both are IFN dependent and abrogated by a monoclonal antibody which blocks IFNAR action. The beta-PTyr component may represent an important difference in the action of IFN-beta as compared with IFN-alpha in their shared receptor system.

Amino Acid Sequence↗
PubMed1992

Inhibition of Friend leukemia cell visceral metastases by a new monoclonal antibody and role of the immune system of the host in its action.

We developed a syngeneic mouse IgG2a monoclonal antibody (MAb) A9D41 directed against the Friend leukemia virus envelope gp70 antigen present on the cell surface membranes of virus producer 3C18 Friend leukemia cells (FLC). A9D41 showed a marked antitumor activity in DBA/2 mice given injections of gp70 positive 3C18 FLC, but it was ineffective in mice given injections of gp70 negative 745 FLC or unrelated tumor cells. A9D41 was particularly effective in inhibiting the development of 3C18 FLC liver and spleen metastases. MAb was also effective as adjuvant therapy in inhibiting visceral metastases after excision of an established s.c. FLC tumor, and combined therapy of A9D41 with mouse interferon alpha/beta was more effective than MAb or interferon alpha/beta alone. The immune system of the host played a decisive role in the antimetastatic action of A9D41. Thus, although MAb was cytotoxic for 3C18 FLC in vitro in the presence of rabbit complement, the F(ab')2 fragment was ineffective in vivo, and the antitumor effect of MAb was abolished in mice treated with an antibody to CD4 and diminished in natural killer cell-deficient beige and athymic nude mice. MAb-treated mice surviving injection of FLC developed an immune response to 3C18 FLC.

Animals↗
PubMed1991

Host humoral and cellular immune mechanisms in the continued suppression of Friend erythroleukemia metastases after interferon alpha/beta treatment in mice.

DBA/2 mice were injected intravenously with 2 x 10(6) 3C18 Friend erythroleukemia cells (FLC), a cell line resistant to interferon alpha/beta (IFN-alpha/beta). Although daily administration of mouse IFN-alpha/beta markedly increased the mean survival time, most IFN-treated mice continued to harbor FLC in different organs. To investigate the mechanisms responsible for this persistent suppression of FLC growth in IFN-treated mice, we undertook a series of adoptive transfer experiments with sera and spleen cells. Sera from FLC-injected, IFN-treated mice were very effective in conferring protection on DBA/2 mice even when injected systemically (intravenously) 18-24 h before intravenous challenge with FLC. These sera also exhibited antitumor activity when injected subcutaneously or intraperitoneally together with FLC. The protective factor in serum was shown to be an immunoglobulin. FLC-injected, IFN-treated mice developed antibodies to FLC demonstrable by radioimmunoassay and complement-dependent cytotoxicity. Sera from these mice recognized a specific 65-kD FLC membrane antigen(s) not detectable on membrane extracts from RBL-5 or ESb tumor cells, or on normal spleen cells. FLC-injected, IFN-treated mice also developed a specific cellular response demonstrable by transfer of protection with spleen cells injected intravenously or subcutaneously. Analysis of the responsible spleen cell populations indicated that the effector cells were neither T nor B cells. These results demonstrating the importance of host humoral and cellular immune mechanisms in the persistent suppression of FLC in IFN-treated mice may be relevant to the use of IFN-alpha/beta in patients in whom tumors may regress and tumor cells may then remain latent for extended periods of time.

Animals↗
PubMed1991

Murine tumor cells expressing the gene for the human interferon alpha beta receptor elicit antibodies in syngeneic mice to the active form of the receptor.

The cellular receptor for the human alpha and beta interferons (IFN) was expressed, by gene transfer, in a murine hepatoma-derived cell line, BTG 9A. Injected subcutaneously into the syngeneic mouse (C57BL/6), the parental and the transfected cells grew and formed tumors which later regressed. More than half the mice bearing tumors derived from cells expressing the receptor, developed IgG antibodies capable of blocking the activity, on human cells, of human recombinant IFN-alpha B, -alpha A, -alpha D and of natural human IFN-beta, but not of recombinant IFN-gamma. Cross-reactivity of human IFN-alpha on murine and bovine cells was unaffected by these antibodies. The binding of human IFN-alpha to solubilized receptors from human lymphoid cell lines was also blocked and complexes of radiolabeled recombinant IFN-alpha A or IFN-alpha B, chemically cross-linked to their human receptor could be immunoprecipitated by the antisera. IFN alpha beta receptor protein, purified by electrophoresis in sodium dodecylsulfate, was not recognized. We conclude that the antibodies are directed against the forms of the IFN alpha beta receptor actually expressed on the membrane.

Animals↗
PubMed1991

An interferon-induced 16-kD protein is present in the membranes of interferon-sensitive but not in interferon-resistant mouse cells.

Human interferon-alpha (IFN-alpha) or IFN-beta has been shown to induce a 17-kD membrane protein in human cells which when eluted from SDS gels inhibited the multiplication of cells of different human cell lines. We show herein that mouse IFN-alpha/beta induces a 16-kD membrane protein in L1210 and Friend erythroleukemia cells sensitive to IFN-alpha/beta, (but not in the derived IFN-alpha/beta-resistant cell lines) as well in primary and monolayer cultures of mouse embryonic fibroblasts and adult mouse hepatocytes, and in suspensions of spleen cells. In addition, IFN-alpha/beta enhanced the expression of an 11-kD membrane protein which could be shown by immunoprecipitation to be beta 2-microglobulin. Anticell proliferation activity was not recovered from the 16-kD fraction of the SDS gels.

Animals↗