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B Ensoli

Publications and source records attributed to B Ensoli.

At least 55 records · Page 3Linked to original sources
PubMed1999

Infection with human immunodeficiency virus-1 increases expression of vascular endothelial cell growth factor in T cells: implications for acquired immunodeficiency syndrome-associated vasculopathy.

Alterations in the vascular system and the onset of angioproliferative lesions such as Kaposi's sarcoma (KS) are common traits of human immunodeficiency virus-1 (HIV-1)-infected patients. To investigate possible factors involved in acquired immunodeficiency syndrome (AIDS)-associated vasculopathy and vascular malfunction, expression of vascular endothelial cell growth factor-A (VEGF-A) was analyzed in HUT 78 T lymphocytes upon infection with HIV-1. VEGF-A was found to be increased in supernatants from infected cells as compared with uninfected cells. In addition, VEGF-A mRNA expression and protein secretion were significantly increased in HUT 78 cells incubated with conditioned medium (CM) derived from HIV-1 chronically infected HUT 78 cells (HIV-TCM) as compared with CM from uninfected cells (TCM). Increase of VEGF-A production in T cells was promoted by inflammatory cytokines (IC) present in HIV-TCM, including tumor necrosis factor alpha (TNFalpha), interferon gamma (IFNgamma), interleukin-1beta (IL-1beta), and IL-6. These IC that have been shown to be increased in sera of HIV-1-infected patients and to be increased by HIV-1 infection or cell activation in these individuals as well as HIV-TCM also increased VEGF-A expression in primary T lymphocytes. Consistent with this, VEGF-A concentrations were found to be higher in sera of HIV-1-infected patients with (mean, 357.1 +/- 197.9 pg/mL) and without KS (mean, 256.7 +/- 137.5 pg/mL) as compared with uninfected individuals (mean, 188.6 +/- 91.7 pg/mL). These data suggest that increased secretion of VEGF-A by T lymphocytes of HIV-1-infected individuals may induce vascular leakage and stimulate proliferation of vascular endothelial cells, which are hallmarks of AIDS-associated vasculopathy and especially of KS development.

Acquired Immunodeficiency Syndrome↗
PubMed1999

DNA immunization with HIV-1 tat mutated in the trans activation domain induces humoral and cellular immune responses against wild-type Tat.

Intramuscular immunization of mice with plasmids encoding two transdominant negative mutants of the HIV-1 Tat protein (Tat22 and Tat22/37) elicited a humoral response to wild-type Tat that is comparable to that induced by inoculation of wild-type tat DNA or Tat protein. The percentage of the responders and the Ab titers continued to increase after three additional DNA boosts and pretreatment with bupivacaine at the site of inoculation, without a significant difference (p > 0.05) among the three groups of mice immunized with mutant and wild-type tat genes. By utilizing synthetic peptides representing the amino acid sequence of Tat, one major B cell epitope was defined within the cysteine-rich domain of Tat. Anti-Tat IgG Abs directed against this epitope were found in mice immunized with all tat DNA constructs, whereas different Tat epitopes were detected in mice immunized with the Tat protein. Similarly, IgG2a was the predominant isotype in DNA-immunized mice, with both mutants and wild-type tat genes, as compared with protein immunization, which induced mostly IgG1 and IgG3. Sera from most immunized mice neutralized the effect of extracellular Tat in activating HIV-1 replication. A cellular response was also elicited as indicated by the proliferation of splenocytes when stimulated with wild-type Tat. These results indicate that the wild-type Tat Ag is recognized by Abs and T cells induced by DNA immunization with mutated tat genes, suggesting the possible use of these Tat transdominant mutants, lacking viral trans activation activity and capable of blocking wild-type Tat activity, in the development of an anti-HIV-1 vaccine.

3T3 Cells↗
PubMed1999

High seroprevalence of antibodies to human herpesvirus-8 in Egyptian children: evidence of nonsexual transmission.

BACKGROUND: In western countries, human herpesvirus-8 (HHV-8) appears to be transmitted mainly by sexual contact. To evaluate the role of other transmission routes, especially in developing countries, we estimated the seroprevalence of HHV-8 in Egyptian children, who, if seropositive, would have acquired the virus through a nonsexual route. METHODS: Sera from 196 children (<1-12 years of age), 20 adolescents (13-20 years of age), and 30 young adults (21-25 years of age) attending a vaccination program in Alexandria, Egypt, were studied. Immunofluorescence assays were used to detect antibodies against HHV-8 lytic-phase antigens (anti-lytic) and latent-phase antigens (anti-latent). Antibodies against Epstein-Barr virus viral cap antigen, cytomegalovirus, and HHV-6 were detected by enzyme-linked immunosorbent assays. Seroprevalence of these herpesviruses was calculated after stratifying the subjects by age. RESULTS: Anti-lytic and anti-latent HHV-8 antibodies were detected in 44.7% and 8.5% of the study participants, respectively. The prevalence of anti-lytic antibodies tended to increase with age, exceeding 50% in children older than 6 years; once children reached the age of 10 years, the prevalence tended to stabilize. The seroprevalence of other herpesviruses tended to be higher than that of HHV-8, ranging from approximately 83% to more than 97% in the 9- to 12-year age group. One- to 3-year-old children had higher titers of antilytic HHV-8 antibodies than children in the other age groups. Anti-latent antibodies were more frequently detected in individuals with high anti-lytic antibody titers. CONCLUSIONS: HHV-8 antibodies are highly prevalent in Egyptian children, suggesting that, in developing countries, HHV-8 infection may be acquired early in life through routes other than sexual transmission. The lower seroprevalence of HHV-8 relative to that of the other herpesviruses suggests that HHV-8 is less transmissible than other common herpesviruses.

Adolescent↗
PubMed1999

IFN-gamma induces endothelial cells to proliferate and to invade the extracellular matrix in response to the HIV-1 Tat protein: implications for AIDS-Kaposi's sarcoma pathogenesis.

Previous studies indicated that the Tat protein of HIV functions as a progression factor in Kaposi's sarcoma (KS), an angioproliferative disease common and aggressive in HIV-1-infected individuals (AIDS-KS). In particular, Tat that is released by infected cells stimulates the growth and invasion of spindle cells of endothelial origin derived from KS lesions (KS cells). Other work suggested that inflammatory cytokines may act as initiating factors in KS since they induce normal endothelial cells to acquire the same phenotype and functional features of KS cells, including the responsiveness to Tat. In this study, we show that among the inflammatory cytokines increased in AIDS-KS lesions, IFN-gamma alone is sufficient to induce endothelial cells to proliferate and to invade the extracellular matrix in response to Tat. This is because IFN-gamma up-regulates the expression and activity of the receptors for Tat identified as the integrins alpha5beta1 and alpha(v)beta3. These results suggest that, by triggering Tat effects, IFN-gamma plays a major role in AIDS-KS pathogenesis.

Acquired Immunodeficiency Syndrome↗
PubMed1999

Expression of human herpesvirus-8 (HHV-8) encoded pathogenic genes in Kaposi's sarcoma (KS) primary lesions.

Transcription of six different HHV-8 specific mRNAs was examined in early- and late-stage KS primary lesions. Expression of the latency-associated T0.7 mRNA and of VP23 mRNA which is a specific marker of lytic/productive infection suggested that HHV-8 is secondarily recruited into the KS lesions by productively infected monocytes, macrophages. From these cells HHV-8 is transmitted to the KS spindle cells, which are latently infected. v-BCL-2, v-MCP-1 and v-IL-6 were not expressed in latently infected KS spindle cells, therefore the impact of these factors in KS pathogenesis appears to be low. By contrast, v-Cyclin D was highly expressed in almost all latently infected spindle cells and may therefore be an important factor triggering progression of late-stage KS lesions.

Aged↗
PubMed1999

Control of SHIV-89.6P-infection of cynomolgus monkeys by HIV-1 Tat protein vaccine.

Vaccine strategies aimed at blocking virus entry have so far failed to induce protection against heterologous viruses. Thus, the control of viral infection and the block of disease onset may represent a more achievable goal of human immunodeficiency virus (HIV) vaccine strategies. Here we show that vaccination of cynomolgus monkeys with a biologically active HIV-1 Tat protein is safe, elicits a broad (humoral and cellular) specific immune response and reduces infection with the highly pathogenic simian-human immunodeficiency virus (SHIV)-89.6P to undetectable levels, preventing the CD4+ T-cell decrease. These results may provide new opportunities for the development of a vaccine against AIDS.

AIDS Vaccines↗
PubMed1999

Alpha interferon inhibits human herpesvirus 8 (HHV-8) reactivation in primary effusion lymphoma cells and reduces HHV-8 load in cultured peripheral blood mononuclear cells.

Infection by human herpesvirus 8 (HHV-8) is associated with the development of Kaposi's sarcoma (KS). Since regression of KS can be achieved by treatment of the patients with alpha interferon (IFN-alpha), we analyzed the effects of IFN-alpha or anti-IFN-alpha antibodies (Ab) on HHV-8 latently infected primary effusion lymphoma-derived cell lines (BCBL-1 and BC-1) and on peripheral blood mononuclear cells (PBMC) from patients with all forms of KS and from at-risk subjects. IFN-alpha inhibited in a dose-dependent manner the amplification of HHV-8 DNA in BCBL-1 cells induced to lytic infection with tetradecanoyl phorbol acetate (TPA). This effect was associated with the inhibition of the expression of HHV-8 nut-1 and kaposin genes that are induced early and several hours, respectively, after TPA treatment. In addition, IFN-alpha inhibited virus production and/or release from BCBL-1 cells. Inhibition of nut-1 and kaposin genes by IFN-alpha was also observed in BC-1 cells induced with n-butyrate. Conversely, the addition of anti-IFN-alpha Ab to TPA-induced BCBL-1 cells resulted in a larger number of mature enveloped particles and in a more extensive cytopathic effect due to the neutralization of the endogenous IFN produced by these cells. IFN was also produced by cultured PBMC from HHV-8-infected individuals, and this was associated with a loss of viral DNA during culture. However, the addition of anti-IFN-alpha Ab or anti-type I IFN receptor Ab promoted the maintenance of HHV-8 DNA in these cells that was associated with the detection of the latency-associated kaposin RNA. Finally, the addition of IFN-alpha reduced the HHV-8 load in PBMC. Thus, IFN-alpha appears to have inhibitory effects on HHV-8 persistent infection of PBMC. These results suggest that, in addition to inhibiting the expression of angiogenic factors that are key to KS development, IFN-alpha may induce KS regression by reducing the HHV-8 load and/or inhibiting virus reactivation.

Genes, Viral↗
PubMed1999

Big but weak: how many pathogenic genes does human herpesvirus-8 need to cause Kaposi's sarcoma? (Review).

Human herpesvirus-8 (HHV-8) is implicated in the pathogenesis of Kaposi's sarcoma (KS). In the last two years several HHV-8 gene products were heralded to 'cause KS' without any evidence that the respective gene is expressed in the tumor cells of KS lesions. In this framework it is of interest that almost 10% of the genes encoded by HHV-8 have been suggested to promote KS development due to either mitogenic, anti-apoptotic, chemoattractive, angiogenic or transforming activities. The rapidly growing number of HHV-8-encoded genes with 'KS causing' activities raises the question of why HHV-8 may need so many genes to trigger growth of KS that appears to be more closely related to a hyperplasia than to a real sarcoma. In this review an overview of the current knowledge of HHV-8 gene expressions in KS lesions in vivo is presented.

Genes, Viral↗
PubMed1998

Purified Tat induces inflammatory response genes in Kaposi's sarcoma cells.

OBJECTIVE: Kaposi's sarcoma (KS) is a neoplasm strongly associated with HIV-1 infection and marked by leukocytic infiltration. The infiltrating leukocytes are a possible source of inflammatory cytokines, human herpesvirus 8 (HHV8) and the HIV-1 transactivator protein Tat. This study examines whether Tat directly induces expression of cellular adhesion molecules and cytokines in KS cells and whether this induction differs in kinetics and magnitude from induction by tumour necrosis factor (TNF) alpha. DESIGN AND METHOD: Changes in gene expression in response to recombinant Tat compared with those to TNFalpha were evaluated at the messenger (m) RNA and protein level using cells that were cultured from KS lesions. RESULTS: Tat induced the expression of the adhesion molecules vascular cell adhesion molecule 1 (VCAM-1) and intercellular adhesion molecule 1 (ICAM-1) and the cytokines monocyte chemoattractant protein 1 (MCP-1) and interleukin 6 (IL-6). The inductions were observed at both the protein and mRNA levels. The pattern of mRNA induction over time in response to Tat differed from that to TNFalpha, with higher peak levels that occurred earlier in response to Tat. The expression of these genes is, in part, regulated by the transcription factor NF-kappaB. Tat and TNFalpha activated comparable levels of NF-kappaB. CONCLUSIONS: The ability of the HIV-1 Tat to induce the expression of genes with kinetics that are distinct from those seen in TNFalpha induction suggests that mechanisms in addition to activation of NF-kappaB contribute to the observed induction. Tat may contribute to the pathogenesis of AIDS-related KS through induction of cellular genes that are pro-proliferative and proinflammatory and may enhance the recruitment of leukocytes, which are a possible source of further cytokines, Tat and HHV8.

AIDS-Related Opportunistic Infections↗
PubMed1998

Prevalence and determinants of anti-lytic and anti-latent antibodies to human herpesvirus-8 among Italian individuals at risk of sexually and parenterally transmitted infections.

Three hundred seventy-nine individuals [137 non-injecting drug using (non-IDU) heterosexuals, 130 homosexual men and 112 IDU] attending the human immunodeficiency virus (HIV) testing program of a sexually transmitted disease (STD) clinic in Rome were studied to estimate the prevalence and to identify the modalities of transmission of human herpesvirus-8 (HHV-8) infection. Serological analysis was performed by using an immunofluorescence assay able to detect anti-latent and anti-lytic HHV-8 antibodies. Twelve acquired immunodeficiency syndrome (AIDS)-Kaposi's sarcoma (KS) patients and 94 blood donors were tested as reference population groups. Anti-lytic antibodies were detected in 185 (48.8%) individuals; 52 of them (13.7%) also had anti-latent antibodies. Both anti-lytic and anti-latent antibody prevalence were higher among homosexual men (66.9% and 27.7%, respectively) than among IDU (49.1% and 8.0%, respectively) and non-IDU heterosexuals (31.4% and 5.1%, respectively), and tended to increase with age. Anti-lytic HHV-8 antibodies were associated with syphilis [odds ratio (OR)=3.81] but not with hepatitis C virus (HCV) seropositivity. HIV-infected homosexual men were more likely to have HHV-8 antibodies than those who were HIV-negative. When using anti-latent antibodies the direction of the OR remained the same, although the associations did not often reach statistical significance. Among AIDS-KS patients, 83.3% had anti-lytic and 66.6% had anti-latent antibodies. Among blood donors, 28% had anti-lytic antibodies and 2 of them (2.1%) also had anti-latent antibodies. Our data indicate that HHV-8 seroprevalence increases with age and is higher among homosexual men, particularly those infected with HIV. This is consistent with sexual transmission of HHV-8 infection. In addition, the presence of HHV-8 antibodies in HIV-negative non-IDU heterosexual contacts and in healthy blood donors is consistent with the high incidence of classic KS in Italy.

Adolescent↗
PubMed1998

gamma-Interferon produced by CD8+ T cells infiltrating Kaposi's sarcoma induces spindle cells with angiogenic phenotype and synergy with human immunodeficiency virus-1 Tat protein: an immune response to human herpesvirus-8 infection?

Kaposi's sarcoma (KS) is an angioproliferative disease associated with infection by the human herpesvirus-8 (HHV-8). HHV-8 possesses genes including homologs of interleukin-8 (IL-8) receptor, Bcl-2, and cyclin D, which can potentially transform the host cell. However, the expression of these genes in KS tissues is very low or undetectable and HHV-8 does not seem to transform human cells in vitro. In addition, KS may not be a true cancer at least in the early stage. This indicated that besides its transforming potential, HHV-8 may act in KS pathogenesis also through indirect mechanisms. Evidence suggests that KS may start as an inflammatory-angiogenic lesion mediated by cytokines. However, little is known on the nature of the inflammatory cell infiltration present in KS, on the type of cytokines produced and on their role in KS, and whether this correlates with the presence of HHV-8. Here we show that both acquired immunodeficiency syndrome (AIDS)-KS and classical KS (C-KS) lesions are infiltrated by CD8+ T cells and CD14+/CD68+ monocytes-macrophages producing high levels of gamma-interferon (gamma IFN) which, in turn, promotes the formation of KS spindle cells with angiogenic phenotype. gamma IFN, in fact, induces endothelial cells to acquire the same features of KS cells, including the spindle morphology and the pattern of cell marker expression. In addition, endothelial cells activated by gamma IFN induce angiogenic lesions in nude mice closely resembling early KS. These KS-like lesions are accompanied by production of basic fibroblast growth factor, an angiogenic factor highly expressed in primary lesions that mediates angiogenesis and spindle cell growth. The formation of KS-like lesions is upregulated by the human immunodeficiency virus Tat protein demonstrating its role as a progression factor in AIDS-KS. Finally, gamma IFN and HLA-DR expression correlate with the presence of HHV-8 in lesional and uninvolved tissues from the same patients. As HHV-8 infects both mononuclear cells infiltrating KS lesions and KS spindle cells, these results suggest that HHV-8 may elicit or participate in a local immune response characterized by infiltration of CD8+ T cells and intense production of gamma IFN which, in turn, plays a key role in KS development.

Animals↗
PubMed1998

gamma-Interferon production in peripheral blood mononuclear cells and tumor infiltrating lymphocytes from Kaposi's sarcoma patients: correlation with the presence of human herpesvirus-8 in peripheral blood mononuclear cells and lesional macrophages.

Evidence indicates that, at least in the early stage, Kaposi's sarcoma (KS) is a cytokine-mediated disease and that it is consistently associated with a novel herpesvirus termed human herpesvirus-8 (HHV-8). To gain insights into the mechanisms by which cytokines and HHV-8 may cooperate in disease pathogenesis, we examined the phenotype, the Th1 (gamma-interferon [gamma IFN]) and Th2 (interleukin-4 [IL-4] cytokine profile and the presence of HHV-8 in peripheral blood mononuclear cells (PBMC), tumor-infiltrating lymphocytes (TIL), and spindle cell cultures derived from skin lesions of patients affected by classical KS (C-KS) and acquired immunodeficiency syndrome (AIDS)-associated KS (AIDS-KS). TIL and spindle cell cultures were examined at day 0 or after culture in conditioned media from activated T cells (TCM) that contain the same cytokines increased in KS tissues. No differences were found in the immunophenotype of PBMC from C-KS patients versus controls, except for AIDS-KS patients who showed a T-CD8+ expansion. However, a preferential infiltration of T-CD8+ cells was found in all KS lesions examined, which was maintained after culture of TIL in TCM. gamma IFN production was found in both PBMC and cultures derived from all KS examined; some IL-4 positive supernatants were found only in three AIDS-KS cases. Uninvolved skin did not show appreciable lymphocyte infiltration or cytokine production. The culture conditions of the lesional skin allowed also the appearance of adherent, spindle-like cells bearing markers of tissue macrophages. Finally, most or all of the PBMC, lesions, and macrophagic cell cultures from the skin lesions were found to be positive for HHV-8 infection by nested polymerase chain reaction (PCR). These findings indicate that patients with KS express a Th1 phenotype with a prevalent gamma IFN production, likely accounted for by the local T-CD8+ infiltration. By analogy with other viral infections (i.e., Epstein-Barr virus), this suggests that in loco recruitment of lymphoid cells and the subsequent gamma IFN production may be in response to or elicited by HHV-8 that was found in both PBMC and macrophagic cell cultures from the lesions of the same patients.

Adult↗
PubMed1998

Inflammatory cytokines induce the expression of basic fibroblast growth factor (bFGF) isoforms required for the growth of Kaposi's sarcoma and endothelial cells through the activation of AP-1 response elements in the bFGF promoter.

BACKGROUND: The growth of Kaposi's sarcoma (KS) spindle cells is dependent on a number of inflammatory cytokines as well as the autocrine growth factor, basic fibroblast growth factor (bFGF). Moreover, inflammatory cytokines, found at increased levels in KS lesions, promote bFGF production in KS and endothelial cells. OBJECTIVES: To determine the induction of bFGF isoforms, role of bFGF in cell growth and activation of the bFGF promoter by inflammatory cytokines. DESIGN AND METHOD: 3H-Thymidine uptake, bFGF immunoblotting and transfection of dominant-negative MAP kinase components were used to study the effect of cytokines on the bFGF promoter, bFGF isoform expression and proliferation of KS cells. RESULTS: Treatment with oncostatin M (OSM), interleukin (IL)-1 and tumor necrosis factor (TNF)-alpha induced the expression of 18, 22 and 24 kDa bFGF isoforms in KS and human umbilical vein endothelial cells (HUVEC). Antisense bFGF oligonucleotides interfered in the induction of KS cell proliferation by individual cytokines. OSM, IL-1 and TNF-alpha induced the transcriptional activation of a bFGF promoter reporter gene in parallel with the activation of an AP-1 reporter. Dominant-negative ERK and dominant-negative JNK mutants interfered in cytokine-induced activation of these reporters in accordance with the role of the MAP kinase cascades in individual cytokine signaling pathways. CONCLUSIONS: OSM, IL-1 and TNF-alpha induce KS cell growth by inducing the expression of various bFGF isoforms. Moreover, bFGF production by KS and HUVEC is dependent on the activation of the ERK and JNK cascades, which result in the transcriptional activation of the bFGF promoter.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Basic fibroblast growth factor supports human olfactory neurogenesis by autocrine/paracrine mechanisms.

Throughout life, olfactory sensory neurons are renewed from a population of dividing stem cells. Little is known about the molecular mechanisms that regulate the activation, self-renewal and differentiation of olfactory neuronal precursors; however, evidence indicates that soluble mediators may play a central role in olfactory neurogenesis. To identify molecules that regulate olfactory self-renewal and differentiation, we have recently established, cloned and propagated in vitro primary long-term cell cultures from the human fetal olfactory neuroepithelium. Here we show that primary human olfactory neuroblasts synthesize and release biologically active basic fibroblast growth factor which, in turn, supports neuroblast growth by autocrine/paracrine mechanisms. The growth-promoting activity of basic fibroblast growth factor is dose dependent and is accompanied by morphological changes of the cells and by an increase in the expression of neuronal-related genes. These observations indicate that endogenous basic fibroblast growth factor participates in controlling olfactory self-renewal and suggest that this cytokine represents a key regulatory element of olfactory neurogenesis.

Cell Differentiation↗