Treatment of HIV-infected fibroblasts with human leukocyte antigen (HLA)-DR-inductive cytokines leads to infectious virions with newly acquired HLA-DR.
Explore the source record for details and available documents.
Carrier Proteins↗
Biomedical subjects
F Dianzani
Publications and source records attributed to F Dianzani.
Biological and clinical significance of neutralizing and binding antibodies to interferon-alpha (IFN-alpha) during therapy for chronic hepatitis C.
It is known that IFN therapy can induce the development of anti-IFN antibodies. In order to evaluate the biological and clinical significance of both neutralizing (NA) and non-neutralizing (binding) antibodies, 123 patients with chronic hepatitis C treated with recombinant IFN-alpha were examined. Among them, 15 were positive for NA and 24 for binding antibodies. The kinetics of NA appearance show that, in general, they develop early during the first 3 months of treatment. Moreover, NA seem to be clinically relevant, since they may be responsible for non-responsiveness to treatment in 53% of patients who develop them. The evaluation of the clinical significance of binding antibodies is more difficult. They appear significantly earlier in non-responders than in responders, but no differences were observed in the overall percentage of seroconversion between responders and non-responders. Thus, it is not possible at the moment to establish their possible role in inducing non-responsiveness.
Alanine Transaminase↗
Recombinant gp120 induces IL-10 in resting peripheral blood mononuclear cells; correlation with the induction of other cytokines.
Immunological abnormalities present in HIV-1-infected individuals often reflect an imbalance of cytokine production. The HIV-1 gp120 has the ability to induce a number of cytokines, and to enhance immunoglobulin release by normal peripheral blood mononuclear cells (PBMC) in vitro, in the absence of IL-2 production and of lymphoproliferation. This study provides evidence that gp120 is a potent IL-10 inducer in normal PBMC cultures. The pattern of other cytokines induced by gp120 includes interferon-alpha (IFN-alpha) and IFN-gamma, tumour necrosis factor-alpha (TNF-alpha), IL-6, IL-1 alpha and -beta, and not IL-2 and IL-4. These findings further define the pattern of cytokine release induced by gp120 on human resting PBMC. Furthermore, the present findings roughly parallel those observed both in the sera of patients and in the mononuclear cells from HIV+ individuals early after infection, suggesting that gp120 could be a good candidate as one of the agents responsible for cytokine dysregulation observed in HIV-1-infected individuals.
Biopterins↗
Identification of an amino acid substitution involved in the reduction of sensitivity of HIV-1 to an inhibitor of viral proteinase.
Clones derived from HIV variants previously characterized as resistant to Ro31-8959, an inhibitor of viral proteinase (PR), were sequenced. Substitution of glycine by valine at position 48 of the PR protein was found. None of the 20 clones derived from wild type HTLV-IIIB contain this mutation. Since such a position is located in a conserved region of PR, it is possible that the substitution can affect the interaction of the enzyme with the inhibitor.
Base Sequence↗
T cell growth-promoting activity of interferon-gamma. Mitogenic effect of the recombinant cytokine on cells from a human T-chronic lymphocytic leukemia.
Interferon-gamma (IFN-gamma) has previously been described as exerting a growth factor activity for murine and human stimulated normal T lymphocytes, in addition to its established role in regulating the cytotoxic activity of T and NK cells. We analyzed the effect of human recombinant IFN-gamma on the proliferation of leukemic lymphocytes isolated from the peripheral blood of a patient affected by a T-cell chronic lymphocytic leukemia (T-CLL). Incubation with IFN-gamma induced the proliferation of unstimulated leukemic cells. Cell proliferation was maximal after 6 days of culture with the cytokine; the half-maximal effect of IFN-gamma was observed at a concentration of approximately 800 U/ml. We also measured the production of IFN-gamma by leukemic cells. Cells incubated in control medium released small quantities of IFN-gamma activity, while the addition of low doses of the exogenous cytokine to the cell cultures induced high levels of IFN-gamma mRNA and protein production. Furthermore, anti-HLA class I monoclonal antibodies, that exert a mitogenic effect on these neoplastic lymphocytes, also induced the IFN-gamma gene expression in the same cells. These results indicate that IFN-gamma may stimulate the proliferation of human neoplastic T cells and suggest that this cytokine might have a role in the expansion of T-leukemic cell clones in vivo.
Antibodies, Monoclonal↗
Antibodies to interferon alpha in patients.
A massive amount of information on interferons (IFNs) has been gathered since their original description as antiviral agents in 1957. Human IFNs have now been used clinically for over a decade and their therapeutic efficacy has been well established for some human neoplasias and viral diseases. During these studies, it has also been documented that some of the patients treated with IFNs can develop antibodies to IFNs which can affect their therapeutic efficacy. Here, it is summarized what is currently known on the biological and clinical aspects of these antibodies.
Antibodies↗
CD4-positive lymphoid cells rescue HIV-1 replication from abortively infected human primary endothelial cells.
Human primary endothelial cell cultures, derived from umbilical vein (HUVEC), can be infected by different strains of HIV-1, but mature virus production remains undetectable both in supernatants and in cellular extracts. Yet viral DNA is transiently detectable during the first days of infection, but progressively declines during the subsequent days. This finding is characteristic of abortive infections. Co-culture of HUVEC carrying HIV DNA with activated peripheral blood mononuclear cells or with CD4-positive lymphoid cells elicited a massive cpe (syncytia formation and cell degeneration) in the latter cells, caused by the establishment of productive HIV-1 infection. HUVEC infected in the presence of AZT were significantly impaired in the ability to transmit the infection of CD4-positive cells, indicating that active DNA synthesis is required in HUVEC before rescue by CD4-positive cells. These results are of interest in view of the possibility that endothelial cells can play a role in the transmission of HIV-1 infection from infected pregnant women to the foetuses, and, more generally, suggest a potential role of endothelial cells as a transient reservoir of HIV-1.
Antibodies, Monoclonal↗
Coordinate induction of interferon alpha and gamma by recombinant HIV-1 glycoprotein 120.
Similarly to HIV-infected cells, recombinant HIV-1 glycoprotein 120 induces acid-labile interferon production in peripheral blood mononuclear cells from healthy donors. Acid lability of this interferon is due to the presence of both IFN-alpha and -gamma molecules. In fact, although not revealed by neutralization of antiviral activity with antibody to IFN-gamma, the presence of IFN-gamma was shown both immunoenzymatically and by detection of specific mRNA in gp120-stimulated cells. The source of IFN-gamma appears to be a T cell present in the CD4-enriched subpopulation. Cultures treated with monoclonal antibodies to the ICAM-1 and LFA-1 adhesion molecules showed an impaired release of both IFN types after gp120 stimulation, suggesting a crucial role of cell-to-cell interactions in the process leading to IFN production. Our data suggest that the HIV envelope glycoprotein could be responsible for the induction of endogenous IFN-alpha and -gamma observed in AIDS patients.
Cell Adhesion Molecules↗
Potentiation of interferon-alpha in vitro antiviral activity by interferon-gamma is not abrogated by antibody to interferon-gamma.
The addition of minute amounts of recombinant interferon-gamma (IFN-gamma) to recombinant IFN-alpha 2 significantly enhances its antiviral activity. Although this potentiating action of IFN-gamma is destroyed by treatment with acid, it is not significantly affected by treatment with antibodies to IFN-gamma, suggesting that IFN-gamma molecules can interact with cells to potentiate IFN-alpha activity, even in the presence of neutralizing antibodies. Implications of this phenomenon are multifaceted, including the possibility that other IFN activities can be altered synergistically by combinations of different IFN types, even in the presence of specific antibodies, which have been described to occur in vivo in several pathological conditions.
Antibodies↗
2',5'-Oligoadenylate synthetase activity as a responsive marker during interferon therapy for chronic hepatitis C.
The 2',5'-oligoadenylate (2-5A) synthetase is an intracellular enzyme induced by interferon (IFN). We evaluated the serum level of this enzyme in 25 patients affected by chronic hepatitis C and treated with recombinant IFN-alpha 2b. At the end of treatment, 14 patients were classified as responders and 11 as nonresponders. Before therapy initiation no significant differences in 2-5A synthetase levels among the patients were detected, while during therapy responders showed higher mean levels of 2-5A synthetase than nonresponders. An increase in the enzyme activity was observed after 1 month of therapy, and this trend was maintained in the following 2 months. The peak of 2-5A synthetase activity was found at the end of therapy. 2-5A synthetase levels were negatively correlated with serum alanine aminotransferase (ALT). This study suggests that 2-5A synthetase may be a useful marker to monitor IFN efficacy during treatment and to predict the clinical response.
2',5'-Oligoadenylate Synthetase↗
Neutralizing antibodies to recombinant alpha-interferon and response to therapy in chronic hepatitis C virus infection.
Forty-seven patients with chronic hepatitis C were treated with recombinant interferon alpha-2a (rIFN alpha 2a) given subcutaneously in a standard dose of 3 MU thrice weekly for 12 months. Stored baseline sera and monthly samples during treatment were assayed for anti-interferon neutralizing antibodies using the antiviral neutralization bioassay against 5 IU of rIFN alpha 2a. During therapy, 15 of 47 patients (31.9%) developed detectable levels of neutralizing antibodies within 2-8 months after starting treatment. After 12 months of therapy, 26 of 32 antibody-negative patients (81.3%) showed normalization or marked reduction of ALT levels compared to 4 of 15 (26.6%) who developed anti-IFN neutralizing antibodies (p = 0.0009). Four patients demonstrated antiviral response during treatment even in the presence of low levels or late occurrence of neutralizing antibodies. Six of the seven patients who had disease reactivation after an initial response developed high titers of neutralizing antibodies. Our results suggest that reactivation of chronic hepatitis C before completion of therapy seems to be an obvious consequence of anti-IFN neutralizing antibody formation.
Alanine Transaminase↗
Biological basis for the clinical use of interferon.
Interferons are proteins produced by certain cells in response to stimuli such as foreign cells (including tumour cells), bacteria, and viral antigens. They interact both with the interferon producing cells and other cells through production of effector proteins. There are three main types of interferons, known as alpha, beta, and gamma, which have direct antiviral and immunomodulatory effects. Antiviral effects may include inhibition of viral replication, protein synthesis, maturation, or release from infected cells. Immunomodulating effects may include enhancement of macrophage, cytotoxic T cell, and natural killer cell activity. In chronic viral hepatitis, the precise mechanisms of action of alpha interferon are not yet certain. Patients with chronic hepatitis B, however, have been shown to lack endogenous interferon production; those who respond to alpha interferon treatment show a characteristic peak in serum amino-transferase activity before resolution of the infection, indicating an immune reaction. In chronic hepatitis C, the antiviral effect may be more important; patients who respond to alpha interferon tend to have higher values of 2'5' oligo adenylate synthetase, an enzyme induced by interferons that breaks down viral RNA. The clinical relevance of anti-interferon neutralising antibodies produced by some patients during interferon treatment has yet to be firmly established.
Hepatitis B↗
90K protein: a new predictor marker of disease progression in human immunodeficiency virus infection.
A 90,000-Da molecular mass tumor-associated protein has recently been identified in the sera of patients infected by HIV. In this study, we have evaluated the serum levels of 90K for its ability to predict the progression to ARC or AIDS retrospectively in 49 HIV-seropositive subjects who were initially symptom-free. 90K levels were higher in those HIV-seropositive subjects who progressed to ARC or AIDS than in those who had not progressed both at entry into the study and at the latest visit. CD4+ cell number was not different in the two groups at entry but was lower in the progressors at the latest visit. Evaluation of the patterns of change over time showed that 90K increased and CD4+ cells decreased more in progressors than in nonprogressors. During the 3 years preceding the onset of ARC or AIDS, 90K increased regularly while CD4+ cell decrease was later. Elevated levels of 90K (p = 0.007) and lower numbers of CD4+ cells (p = 0.001) were significantly associated with a higher cumulative incidence of ARC or AIDS. These findings suggest that 90K is an early indicator of progression to ARC and AIDS.
AIDS-Related Complex↗
In vitro selection of human immunodeficiency virus type 1 resistant to 3'-azido-3'-deoxythymidine.
3'-Azido-3'-deoxythymidine (AZT)-resistant human immunodeficiency virus type 1 (HIV-1) was obtained by growing HTLV-IIIB in C8166 cell cultures in the presence of inhibitory concentrations of AZT. The AZT-resistant HIV-1 was capable of replicating, as measured by infectious virus yield, and inducing cytopathic effect in the presence of AZT concentrations able to completely suppress the replication of parental HTLV-IIIB. Cloning of the AZT-resistant HIV-1 revealed that a number of different variants of HIV-1 with various degrees of sensitivity to AZT emerged during propagation of HTLV-IIIB in C8166 cells in the presence of the drug. PCR experiments performed on DNA extracted from C8166 cells infected with a resistant strain revealed that viral DNA was produced in the presence of inhibitory concentrations of AZT, while viral DNA in C8166 cells infected with the parental virus was drastically inhibited. Reverse transcriptase isolated from the AZT-resistant HIV-1 variant failed to show resistance to AZT 5'-triphosphate.
Antiviral Agents↗
Resistance of HIV-1 to AZT might also involve the cellular expression of multidrug resistance P-glycoprotein.
Resistance of tumor cells to the antigrowth activity of several cytotoxic compounds has been associated with the expression of the so-called multidrug resistance protein or P-glycoprotein. This article addresses the question whether the expression of such protein could also affect the sensitivity of HIV to AZT. Our data indicate that this possibility does exist. In fact, multidrug-resistant CEM VBL100 cells, which express high levels of P-glycoprotein, are less sensitive to both the antiproliferative activity and the antiviral action of AZT. Additionally, our data suggest that this phenomenon is specifically mediated by P-glycoprotein since trifluoroperazine, which is known to circumvent multidrug resistance due to the action on P-glycoprotein, increases the intracellular accumulation of AZT and affects the sensitivity of HIV to AZT. Although the biological and clinical significance of these observations has still to be established, this study suggests that cellular factors, other than virus itself, should be taken into account to address the phenomenon of drug resistance of HIV.
ATP Binding Cassette Transporter, Subfamily B, Mem↗
Recombinant glycoprotein 120 of human immunodeficiency virus is a potent interferon inducer.
Cells infected with human immunodeficiency virus (HIV) induce antiviral activity in peripheral blood mononuclear cells (PBMC) from healthy donors. This activity is neutralized by anti-interferon-alpha antibody and partially destroyed at pH 2. Previous studies with enriched cell populations and monoclonal antibodies suggest that B lymphocytes are the main IFN-producing cells, and that both CD4 and HLA class II antigens are essential for IFN induction. Since the initial event of HIV infection of CD4+ cells is the interaction of the virus coat glycoprotein gp120 with CD4 molecule, we investigated whether gp120 is responsible for IFN induction. Using PBMC and recombinant gp120 obtained from a baculovirus expression system, dose-dependent induction of antiviral activity was observed with titers approaching 10(3) IU/ml. This induction was blocked in the presence of antibody to gp120. The antiviral activity was characterized as IFN-alpha by neutralization with IFN alpha-specific antibody. Preincubation of PBMC with anti-CD4 or the presence of soluble CD4 during incubation inhibited IFN induction, indicating that interaction of gp120 with cell-associated CD4 is responsible for this induction. Neither lymphoproliferation nor interleukin-2 (IL-2) production was observed during IFN induction. However, class G immunoglobulin secretion was enhanced by gp120, indicating that B cells are direct or indirect targets of gp120 stimulation in this experimental system. Since gp120 is shed from HIV-infected cells and occurs in the serum of acquired immunodeficiency syndrome (AIDS) patients, our data suggest that this glycoprotein is responsible for the induction of endogenous IFN and the polyclonal activation of B cells both of which are observed in AIDS patients.
B-Lymphocytes↗
Acid lability is not an intrinsic property of interferon-alpha induced by HIV-infected cells.
Human immunodeficiency virus (HIV)-infected cells induce acid-labile interferon-alpha (al-IFN-alpha) in cultures of mononuclear cells from peripheral human blood. We have investigated the physiochemical properties of such preparations to elucidate the reasons for acid-lability of this IFN. Al-IFN-alpha is a mixture of both glycosylated and unglycosylated molecules as shown by separation on Concanavalin-A Sepharose. Acid-lability is associated only with glycosylated molecules. Upon chromatography of the glycosylated fraction on Sepharose coupled to IFN-alpha-specific antibody, the portion of the IFN that is retained and eluted with guanidine-HCl is acid-stable, whereas the excluded antiviral activity is acid-labile, and is partially neutralized by antibodies to either IFN-alpha or IFN-gamma. Also, upon further purification of the unglycosylated fraction on the same antibody column, all antiviral activity remains indistinguishable from conventional IFN-alpha. Reconstitution experiments showed that glycosylated material excluded from the anti-IFN-alpha column potentiates antiviral activity of the IFN that is specifically retained by the column. This potentiation is abolished by acid treatment. Similar results are obtained with al-IFN-alpha from the serum of acquired immunodeficiency syndrome (AIDS) patients, indicating that its acid-lability is also the consequence of an acid-labile component that is capable of enhancing the antiviral activity. The potentiation of antiviral activity obtained by combining recombinant preparations of IFN-alpha and IFN-gamma suggests that the cooperating molecule is IFN-gamma.(ABSTRACT TRUNCATED AT 250 WORDS)
Acids↗
Interferon treatments: how to use an endogenous system as a therapeutic agent.
Explore the source record for details and available documents.
Humans↗