Interleukin-2 continuous infusion and angiogenesis surrogate markers in metastatic renal cell carcinoma.
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Adult↗
Biomedical subjects
B Ensoli
Publications and source records attributed to B Ensoli.
HIV-Tat down-regulates telomerase activity in the nucleus of human CD4+ T cells.
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Antibodies, Monoclonal↗
Red blood cell-mediated delivery of recombinant HIV-1 Tat protein in mice induces anti-Tat neutralizing antibodies and CTL.
The immunotherapeutic potential of biologically active HIV-1 Tat protein coupled to autologous red blood cells (RBCs) was evaluated in a mouse model. HIV-1 Tat expressed in Escherichia coli and purified to homogeneity was found to be active in viral trans activation and efficiently internalised by monocyte-derived dendritic cells (MDDCs). The product of HIV-Tat biotinylation and coupling to RBCs by means of a biotin-avidin-biotin bridge, (RBC-Tat), showed no trans activation activity and was still efficiently internalized by MDDCs as compared to uncoupled Tat.Balb/c mice were then immunized with 10 microg of soluble Tat in complete Freund's adjuvant or with 40 ng of Tat coupled on RBCs surface and boosted at week 3, 6 and 25 with 5 microg soluble Tat in incomplete Freund's adjuvant or with 20 ng of RBC-coupled Tat, respectively. Anti-Tat antibody response was similar in both groups; however, 2/6 animals immunized with soluble Tat and 6/6 animals immunized with RBC-Tat developed anti-Tat neutralizing antibodies. In addition, at week 28 cytolytic anti-Tat CTLs were detected in all animals although they were slightly higher in mice immunized with RBC-Tat. These results indicate that RBC-mediated delivery of HIV-1 Tat, in amounts 250 times lower than soluble Tat, is safe and induces specific CTL responses and neutralizing antibodies.
AIDS Vaccines↗
IRF regulation of HIV-1 long terminal repeat activity.
Interferon (IFN) regulatory factors (IRF) constitute a family of transcriptional activators and repressors implicated in multiple biologic processes, including regulation of immune responses and host defense, cytokine signalling, cell growth regulation, and hematopoietic development. All members are characterized by well-conserved DNA binding domains at the N-terminal region that recognize similar DNA sequences termed IRF-binding element/IFN-stimulated response element (IRF-E/ISRE) present on the promoter of the IFN-alpha/beta genes and of some IFN-stimulated genes (ISG). Recently, a sequence homologous to the ISRE has been identified downstream of the 5' human immunodeficiency virus type 1 (HIV-1) long terminal repeat (LTR). This sequence is a binding site for IRF-1 and IRF-2. Deletion of the LTR-ISRE results in impaired LTR promoter activity and decreased synthesis of viral RNA and proteins. Here, we briefly summarize characteristics of IRF-1 and IRF-2 binding to the HIV-1 LTR-ISRE and the data obtained to date on the functionality of this cis-element and on the role of IRF in the regulation of HIV-1 LTR transcriptional activity.
Base Sequence↗
The helical domain of GBP-1 mediates the inhibition of endothelial cell proliferation by inflammatory cytokines.
Inflammatory cytokines (IC) activate endothelial cell adhesiveness for monocytes and inhibit endothelial cell growth. Here we report the identification of the human guanylate binding protein-1 (GBP-1) as the key and specific mediator of the anti-proliferative effect of IC on endothelial cells. GBP-1 expression was induced by IC, downregulated by angiogenic growth factors, and inversely related to cell proliferation both in vitro in microvascular and macrovascular endothelial cells and in vivo in vessel endothelial cells of Kaposi's sarcoma. Experimental modulation of GBP-1 expression demonstrated that GBP-1 mediates selectively the anti-proliferative effect of IC, without affecting endothelial cell adhesiveness for monocytes. GBP-1 anti-proliferative activity did not affect ERK-1/2 activation, occurred in the absence of apoptosis, was found to be independent of the GTPase activity and isoprenylation of the molecule, but was specifically mediated by the C-terminal helical domain of the protein. These results define GBP-1 as an important tool for dissection of the complex activity of IC on endothelial cells, and detection and specific modulation of the IC-activated non-proliferating phenotype of endothelial cells in vascular diseases.
Apoptosis↗
Clearance of human herpesvirus 8 from blood and regression of leukopenia-associated aggressive classic Kaposi's sarcoma during interferon-alpha therapy: a case report.
A human immunodeficiency virus-negative woman with severe classic Kaposi's sarcoma, idiopathic leukopenia, and massive spread of human herpesvirus 8 (HHV-8) in circulating cells showed stable disease remission in response to systemic interferon-alpha treatment that was accompanied by increased CD3(+) and CD4(+) T cell numbers and complete clearance of HHV-8 from the circulation. These results suggest a direct relationship between HHV-8 clearance from blood and regression of Kaposi's sarcoma and are consistent with the in vitro inhibitory effects of interferon-alpha on HHV-8 infection.
Antiviral Agents↗
Serum concentrations of fibroblast growth factor 2 are increased in HIV type 1-infected patients and inversely related to survival probability.
HIV-1-infected patients develop a generalized vasculopathy that is clinically most evident as Kaposi's sarcoma (KS), a multifocally appearing endothelial cell-derived tumor. Fibroblast growth factor 2 (FGF-2) is a potent autocrine and paracrine mitogen of endothelial cells and has been implicated in the cell proliferation and angiogenesis observed in KS. Here we determined by ELISA the FGF-2 serum concentrations in different clinical groups of HIV-1-infected patients. AIDS-KS patients (n = 53) and HIV-1-infected patients without KS (n = 39) revealed significantly increased FGF-2 serum concentrations (median, 4.5 and 4.6 pg/ml, respectively), as compared with the healthy control group (n = 22; median, 2.2 pg/ml; p < 0.01). FGF-2 concentrations were highest in untreated HIV-1-infected patients (median, 8.6 pg/ml) and were significantly decreased in patients undergoing antiretroviral therapy (AZT-median, 4.5 pg/ml; HAART-median, 2.5 pg/ml; p < 0.01). In addition, FGF-2 serum concentrations above 5.2 pg/ml were associated with a statistically significant higher risk of death in HIV-1-infected patients. Multivariate analysis showed that this effect is independent of CD4 levels, localization of KS (cutaneous or visceral), AIDS-defining opportunistic diseases, and therapy. Circulating FGF-2 may contribute to AIDS-associated vasculopathy and may be a sensitive and easily accessible surrogate marker to determine the survival time of HIV-1-infected patients and the efficacy of antiretroviral therapy.
Adult↗
Characterization of HIV-1 Tat proteins mutated in the transactivation domain for prophylactic and therapeutic application.
Previous work from our group showed that genetic immunization of mice with HIV-1 tat genes (tat22 and tat22/37), encoding Tat proteins mutated in the transactivation domain and lacking Tat-transactivating activity, evoke an immune response to wild-type Tat, both humoral and cellular. In the present work we report that the mutated Tat proteins localize within the cells, are released and taken up by the cells in a fashion similar to wild-type Tat. Moreover, the exogenous mutated Tat proteins interfere with the transactivating function of extracellular wild-type Tat. These results support the notion that tat22 and tat22/37 genes may represent good candidates for the development of an anti-HIV-1 vaccine, especially for HIV-1 infected patients.
AIDS Vaccines↗
Vaccination with DNA containing tat coding sequences and unmethylated CpG motifs protects cynomolgus monkeys upon infection with simian/human immunodeficiency virus (SHIV89.6P).
Recent evidence suggests that a CD8-mediated cytotoxic T cell response against the Tat protein of human immunodeficiency virus (HIV)/simian immunodeficiency virus (SIV) controls primary infection after pathogenic virus challenge, and correlates with the status of long-term nonprogressor in humans. Due to the presence of unmethylated CpG sequences, DNA vaccination can boost the innate immunity driving more potent T cell-mediated immune responses. Therefore, cynomolgus monkeys were vaccinated with a tat-expressing vector containing defined unmethylated CpG sequences (pCV-tat). Here it is shown that the intramuscular inoculation of the pCV-tat contained primary infection with the highly pathogenic SHIV89.6P virus preventing the CD4(+) T cell decline in all the vaccinated monkeys. Undetectable virus replication and negative virus isolation correlated in all cases with the presence of anti-Tat CTLs. However, a CD8-mediated non cytolytic antiviral activity was also present in all protected animals. Of note, this activity was absent in the controls but was present in the monkey inoculated with the CpG-rich vector alone that was partially protected against viral challenge (i.e. no virus replication but positive virus isolation). These results suggest that a CTL response against Tat protects against primary infection by blocking virus replication at its early stage, in the absence of sterilizing immunity. Nevertheless, the boost of the innate immunity by CpG sequences can contribute to this protection both by driving more potent CTL responses and by inducing other CD8-mediated antiviral activities. Thus, the CpG-rich tat DNA vaccine may represent a promising candidate for preventive and therapeutic vaccination against AIDS.
AIDS Vaccines↗
Inflammatory cytokines stimulate vascular smooth muscle cells locomotion and growth by enhancing alpha5beta1 integrin expression and function.
The formation of atherosclerotic lesions requires the migration of vascular smooth muscle cells from the media into the intima of the artery and their proliferation. These events, which are preceded and accompanied by inflammation, are modulated by integrin receptors linking vascular smooth muscle cells to extracellular matrix molecules. Among them, fibronectin induces vascular smooth muscle cells to acquire the phenotype they show in the atherosclerotic plaque. Here we show that amounts of interleukin-1 beta, tumor necrosis factor alpha and interferon-gamma as possibly released by activated immune cells infiltrating atherosclerotic lesions, upregulate vascular smooth muscle cell expression of the alpha5beta1 integrin, a fibronectin receptor. This improves vascular smooth muscle cell capability of migrating toward soluble or anchored fibronectin and of adhering to immobilized fibronectin. The latter effect, in turn, augments vascular smooth muscle cell proliferative response to mitogens, as suggested by the increase of intracellular pH. Finally, the effects that inflammatory cytokines have on vascular smooth muscle cell locomotion and growth, are specifically blocked by anti-alpha5beta1 antibodies. As fibronectin and alpha5beta1 levels are augmented in vivo in the atherosclerotic plaques, these findings support the use of integrin antagonists as potential adjuvants in atherosclerosis treatment.
Aorta↗
Identification, molecular cloning and functional characterization of NKp46 and NKp30 natural cytotoxicity receptors in Macaca fascicularis NK cells.
Natural killer (NK) cell recognition and function in humans is regulated by multiple cell surface receptors. The "on" signal leading to NK cell triggering is primarily mediated by natural cytotoxicity receptors (NCR). Analysis of NK cells in primate animal models is of particular relevance because NK cells may play an essential role in host defenses against infections. We analyzed Macaca fascicularis PBMC and in vitro-derived NK cell populations and clones by cytofluorometry, using a wide panel of mAb, and by cytolytic activity assays. In addition, RT-PCR strategy and transient transfections were used to isolate M. fascicularis NCR. NCR-specific mAb reactivity (anti-NKp46 and anti-NKp30) was present on M. fascicularis PBMC and on NK cell cultures. Macaque NCR were functional in both redirected killing and in mAb-mediated masking assays. Cloning of macNKp46 and macNKp30 NCR homologous genes showed a high sequence similarity (86 % and 88 %, respectively) with their human counterparts. Attempts at identifying NKp44 surface reactivity and at cloning the macaque homologue were unsuccessful. NKp46 and NKp30 NCRs, but not NKp44, are highly conserved in M. fascicularis NK cells. This suggests the possibility of a staged appearance of the NCR during phylogenesis and provides a useful tool for the study of natural immunity correlates of protection in primate SIV/SHIV infection models.
Amino Acid Sequence↗
Human herpesvirus-8 and Kaposi's sarcoma: relationship with the multistep concept of tumorigenesis.
Kaposi's sarcoma (KS) develops through discrete inflammatory-angiogenic stages of polyclonal nature (early-stage lesions) to monomorphic nodules of spindle-shaped cells that can be clonal (late-stage lesions) and resemble true sarcomas. Molecular and epidemiological studies indicate that development of KS is tightly associated with infection by the human herpesvirus-8 (HHV-8). However, only individuals with specific conditions of immunodysregulation develop KS. In these individuals the systemic and tissue increase of Th-1-type cytokines (IC) reactivate HHV-8 infection, leading to increased viral load, antibody titers, and an expanded cell tropism that precedes the clinical appearance of KS. Recruitment of the virus into tissues by infected monocytes and other cell types is facilitated by the endothelial cell activation due to IC. In clinical lesions, HHV-8 infection increases with lesion stage and in late-stage lesions most of the spindle cells are latently infected, whereas only few lyrically infected cells are present, suggesting that latent genes may have a role in the transformation of the early inflammatory-hyperplastic lesion into a real sarcoma. The development of tumors, however, is regulated through a multistep process based on the acquisition by cells of several different capabilities leading to malignant growth. Here we review the available data on the expression of HHV-8-encoded genes in primary KS lesions and, in view of their biological activity, analyze their potential function in different steps of tumorigenesis. By this pragmatic approach interesting insights into potential key functions of HHV-8-encoded genes are found and steps of potential cooperativity with other viral factors (HIV-1-Tat) in the pathogenesis of KS are identified.
Gene Expression Regulation, Neoplastic↗
Reactivation and role of HHV-8 in Kaposi's sarcoma initiation.
Kaposi's sarcoma (KS) is an angioproliferative disease occurring in several clinical-epidemio-logic forms but all associated with infection by the human herpesvirus-8 (HHV-8). At least in early stages, KS is a reactive disease associated with a state of immune dysregulation characterized by CD8+ T-cell activation and production of Th1-type inflammatory cytokines (IC) that precedes lesion development. In fact, evidence indicates that IC can trigger lesion formation by inducing the activation of endothelial cells that leads to adhesion and tissue extravasation of lymphomonocytes, spindle cell formation, and angiogenesis, and HHV-8 reactivation that, in turn, leads to virus spread to all circulating cell types and virus dissemination into tissues. Due to virus escape mechanisms and deficient immune responses toward HHV-8, virus reactivation and spread are not controlled by the immune system but induce immune responses that may paradoxically exacerbate the reactive process. The virus is recruited into "activated" tissue sites where it finds an optimal environment for growth. In fact, viral load is very low in early lesions, whereas almost all spindle cells are infected in late-stage lesions. Although early KS is a reactive process of polyclonal nature that can regress, in time and in the presence of immunodeficiency, it can progress to a true sarcoma. This is likely due to the long-lasting expression of HHV-8 latency genes in spindle cells associated with the deregulated expression of oncogenes and oncosuppressor genes and, for AIDS-KS, with the effects of the HIV-1 Tat protein.
Cytokines↗
Biology of Kaposi's sarcoma.
Kaposi's sarcoma (KS) is an angioproliferative disease occurring in several different clinical-epidemiological forms that, however, share the same histological traits and are all associated with infection by the human herpesvirus 8 (HHV8). KS initiates in a context of immune dysregulation characterised by CD8+ T cell activation and the production of Th1-type cytokines that induce a generalised activation of endothelial cells leading to adhesion and tissue extravasation of lympho-monocytes, spindle cell formation and angiogenesis. These phenomena are triggered or enhanced by infection with HHV8 that, in turn, is reactivated by the same cytokines. Productively-infected circulating cells are recruited into 'activated' tissue sites where HHV8 finds an optimal environment for establishing a persistent, latent infection of KS spindle cells (KSC). HHV8 dissemination is favoured by virus escape mechanisms and immune dysregulation, and leads to immune responses that are not effective against the virus but, paradoxically, exacerbates the reactive process. Although early KS is a reactive process of polyclonal nature that can regress, in time it can progress in to a true sarcoma. The progression of KS appears to be due to the deregulated expression of oncogenes and oncosuppressor genes, to the long-lasting expression of the HHV8 latency genes and, for AIDS-KS, is promoted by the proliferative and angiogenic effects of the HIV-1 Tat protein.
Antigens, Viral↗
Interactions between endothelial cells and HIV-1.
Endothelial cells (EC) participate in inflammatory and immune reactions by producing and responding to soluble mediators. Human immunodeficiency virus (HIV)-1 profoundly alters the features of EC. In some anatomical districts, they are infected by the virus and may represent a relevant reservoir. During lymphomononuclear cell diapedesis, EC activate virus replication in crossing cells. Direct or indirect damage of EC is particularly relevant in central nervous system, where blood-brain barrier perturbation is pivotal in neuronal degeneration. The observed alterations of EC adhesive properties contribute in altered leukocyte traffic from blood to lymphoid organs and tissues and play a role in the onset of immune surveillance alteration. These alterations of EC functions are relevant for the general vasculopathy, which marks the acquired immunodeficiency syndrome, and in particular are instrumental in the pathogenesis of Kaposi's sarcoma. Here we discuss the biological and molecular activation of EC in HIV-1 infection that represents the basis to understand the pathogenesis of HIV-1 associated vascular diseases.
Endothelium, Vascular↗
A seroprevalence study of human herpesvirus type 8 (HHV8) in eastern and Central Africa and in the Mediterranean area.
Human herpes virus type 8 (HHV8) is the major determinant of Kaposi's sarcoma (KS), a neoplasm with wide geographic variations in incidence rates. To assess the prevalence of HHV8 infection among populations with differing rates of KS, we used sera from 1,402 persons (Central Africa: Cameroon, n = 293, age range: 5-40; eastern Africa: Uganda, n = 315, age range: 1-64: Mediterranean area: Egypt, n = 236, age range: 13-19: Italy, blood donors n = 134, age range: 20-67: Italy. HIV seroconverters n = 424, age range: 16-65). Serum samples were tested for antibodies to lytic and latent antigens of HHV8 using two immunofluorescence assays. HHV8 prevalence was evaluated according to geographic area, gender and age groups. Overall, the highest prevalence of HHV8 lytic antigens (47.5%) was recorded among children and adults in Africa. Approximately 40% of children and adolescents from Egypt and of Italian HIV-positive persons (39.9%) were HHV8 seropositive. In eastern and Central Africa and in Egypt, no differences emerged between males and females for both types of HHV8 antibodies. Conversely, Italian females were at lower HHV8 risk than their male counterparts. Moreover the prevalence of HHV8 infection tended to increase with age. This investigation partially confirms that HHV8 infection mirrors incidence rates of KS. The high prevalence of HHV8 infection in newborns, children and adolescents in Egypt, in eastern and in Central Africa strongly suggests the existence of transmission modes other than sexual.
Adolescent↗
Comparison of early plasma RNA loads in different macaque species and the impact of different routes of exposure on SIV/SHIV infection.
Various simian immunodeficiency virus (SIV)sm/mac and simian/human immunodeficiency virus (SHIV) strains are used in different macaque species to study AIDS pathogenesis, as well as to evaluate candidate vaccine and anti-retroviral drugs efficacy. In this study we investigated the effect of route of infection, species of macaques and nature of virus stock on early plasma viral RNA load. We monitored the plasma RNA concentrations of 63 rhesus (Macaca mulatta) and cynomolgus macaques (Macaca fascicularis) infected with well-characterised virus stocks administered either by oral, rectal, vaginal or intravenous (i.v.) routes. In SIV(mac)-infected macaques, no significant difference in plasma RNA loads was observed between the rectal, oral and i.v. routes of infection. Cynomolgus macaques developed lower steady state SIV plasma RNA concentrations compared with rhesus macaques and no significant difference was observed between rectal and i.v. routes of infection. In SHIV(89.6p)-infected macaques, no difference between species or between route of infection was observed with this particular chimeric virus.
AIDS Vaccines↗
Prevalence, incidence and correlates of HHV-8/KSHV infection and Kaposi's sarcoma in renal and liver transplant recipients.
BACKGROUND: To determine whether the incidence of HHV-8/KSHV infection and the risk of developing KS among organ transplant recipients differ by type of organ transplanted, we calculated the rate of HHV-8/KSHV seroconversion and the risk of developing KS among renal and liver transplant recipients. METHODS: The study population consisted of renal and liver transplant recipients recruited in two transplant centres in Rome, Italy. Both pre-transplant and post-transplant serum samples were available for all participants. The prevalence of HHV-8/KSHV infection before transplantation was calculated. To determine risk factors for infection, we calculated ORs and 95% CI. Seroconversion rates (i.e. attack rates) after transplantation were also calculated. Differences in attack rates were calculated using a binomial test for proportions. RESULTS: Of the 130 participants, 21 (16.1%) were HHV-8/KSHV-positive before transplantation. Women were more likely to be infected than men, whereas no difference was observed by type of organ transplanted. Of the 109 initially negative individuals, 13 (11.9%) developed anti-HHV-8/KSHV antibodies after transplantation. The incidence of HHV-8/KSHV infection tended to be higher among liver transplant recipients. Four renal transplant recipients and none of the liver transplant recipients developed KS after transplantation. The risk of KS was higher among recipients who were already HHV-8/KSHV-positive before transplantation. CONCLUSIONS: HHV-8/KSHV seroconversion rates appear to be higher among liver transplant recipients, compared to renal transplant recipients. However, renal transplant recipients tend to have a higher risk of KS. HHV-8/KSHV reactivation appears to play a greater role on the risk of KS than incident infections.
Adolescent↗