Biomedical subjects

Mauro Andreotti

Publications and source records attributed to Mauro Andreotti.

12 recordsLinked to original sources

PubMed2007

Triple antiretroviral prophylaxis administered during pregnancy and after delivery significantly reduces breast milk viral load: a study within the Drug Resource Enhancement Against AIDS and Malnutrition Program.

BACKGROUND: The administration of antiretroviral therapy to lactating women could represent a possible strategy to reduce postnatal HIV transmission. In this study, we assessed the effect of antiretroviral treatment on breast milk viral load and determined plasma and breast milk drug concentrations in pregnant women receiving highly active antiretroviral therapy (HAART). METHODS: We studied 40 women receiving zidovudine, lamivudine, and nevirapine from 28 weeks of gestation to 1 month postpartum (group A) and 40 untreated pregnant women (group B). Blood and breast milk samples were collected at delivery and 7 days postpartum. RESULTS: Women in group A had received a median of 85 days of therapy before delivery. Median breast milk concentrations of nevirapine, lamivudine, and zidovudine were 0.6, 1.8, and 1.1 times, respectively, those in maternal plasma. HIV RNA levels in breast milk were significantly lower in group A than in group B (median of 2.3 vs. 3.4 log at delivery and 1.9 vs. 3.6 log at day 7; P < 0.001 for both comparisons). CONCLUSIONS: Antiretroviral drugs administered during the last trimester of pregnancy and after delivery reach levels similar to or higher than plasma concentrations in breast milk and can significantly reduce HIV RNA levels. Our data support the potential role of maternal HAART prophylaxis in reducing the risk of breast-feeding-associated transmission.

Adolescent↗

PubMed2006

Novel bifunctional quinolonyl diketo acid derivatives as HIV-1 integrase inhibitors: design, synthesis, biological activities, and mechanism of action.

The virally encoded integrase protein is an essential enzyme in the life cycle of the HIV-1 virus and represents an attractive and validated target in the development of therapeutics against HIV infection. Drugs that selectively inhibit this enzyme, when used in combination with inhibitors of reverse transcriptase and protease, are believed to be highly effective in suppressing the viral replication. Among the HIV-1 integrase inhibitors, the beta-diketo acids (DKAs) represent a major lead for anti-HIV-1 drug development. In this study, novel bifunctional quinolonyl diketo acid derivatives were designed, synthesized, and tested for their inhibitory ability against HIV-1 integrase. The compounds are potent inhibitors of integrase activity. Particularly, derivative 8 is a potent IN inhibitor for both steps of the reaction (3'-processing and strand transfer) and exhibits both high antiviral activity against HIV-1 infected cells and low cytotoxicity. Molecular modeling studies provide a plausible mechanism of action, which is consistent with ligand SARs and enzyme photo-cross-linking experiments.

Catalytic Domain↗

PubMed2006

IFN-alpha-conditioned dendritic cells are highly efficient in inducing cross-priming CD8(+) T cells against exogenous viral antigens.

Dendritic cells (DC) generated after a short-term exposure of monocytes to IFN-alpha and GM-CSF (IFN-DC) are highly effective in inducing cross-priming of CD8(+ )T cells against viral antigens. We have investigated the mechanisms responsible for the special attitude of these DC and compared their activity with that of reference DC. Antigen uptake and endosomal processing capabilities were similar for IFN-DC and IL-4-derived DC. Both DC types efficiently cross-presented soluble HCV NS3 protein to the specific CD8(+) T cell clone, even though IFN-DC were superior in cross-presenting low amounts of viral antigens. Moreover, when DC were pulsed with inactivated HIV-1 and injected into hu-PBL-SCID mice, the generation of virus-specific CD8(+ )T cells was markedly higher in animals immunized with IFN-DC than in mice immunized with CD40L-matured IL-4-DC. Of interest, in experiments with purified CD8(+ )T cells, IFN-DC were superior with respect to CD40L-matured IL-4-DC in inducing in vitro cross-priming of HIV-specific CD8(+ )T cells. This property correlated with enhanced potential to express the specific subunits of the IL-23 and IL-27 cytokines. These results suggest that IFN-DC are directly licensed for an efficient CD8(+) T cell priming by mechanisms likely involving enhanced antigen presentation and special attitude to produce IL-12 family cytokines.

Animals↗

PubMed2006

Development of a human immunodeficiency virus vector-based, single-cycle assay for evaluation of anti-integrase compounds.

Therapeutic strategies aimed at inhibiting human immunodeficiency virus type 1 (HIV-1) replication employ a combination of drugs targeted to two viral enzymes (reverse transcriptase and protease) and to the viral entry/fusion step. However, the high propensity of HIV-1 to develop resistance makes the development of novel compounds targeting different steps of the HIV-1 life cycle essential. Among these, integrase (IN) inhibitors have successfully passed the early phases of clinical development. By preventing integration, IN inhibitors preclude viral replication while allowing production of extrachromosomal forms of viral DNA (E-DNA). Here, we describe an improved and standardized assay aimed at evaluating IN inhibitors by taking advantage of the transcriptional activity of E-DNA produced by HIV-derived vectors in the absence of replication-competent virus. In this context, the use of the firefly luciferase gene as a reporter gene provides a rapid and quantitative measure of viral-vector infectivity, thus making it a safe and cost-effective assay for evaluating novel IN inhibitors.

Cell Line↗

PubMed2005

Residual viraemia in subjects with chronic HIV infection and viral load < 50 copies/ml: the impact of highly active antiretroviral therapy.

OBJECTIVE: To determine factors associated with < 2.5 copies/ml plasma HIV RNA in subjects treated with highly active antiretroviral therapy (HAART) and with viraemia < 50 copies/ml. DESIGN: Cross-sectional analysis of 84 HIV-positive patients taking HAART with plasma HIV RNA < 50 copies/ml for at least 6 months and no history of virological failure. METHODS: Current HAART therapy was based on a non-nucleoside reverse transcriptase inhibitor (NNRTI) in 66%, a protease inhibitor in 26% and nucleoside reverse transcriptase inhibitors in 7%. Viraemia levels were measured using a modified ultrasensitive Roche Amplicor HIV-1 Monitor test able to quantify plasma HIV RNA to a lower limit of 2.5 copies /ml; proviral DNA was measured with a real-time polymerase chain reaction assay. Analysis of variance and multiple logistic regression analysis were utilized to test for associations between residual replication and other variables. RESULTS: Residual HIV viraemia > 2.5 copies/ml was found in 50% of subjects; 94% of subjects had detectable proviral DNA (>or= 20 copies/10(6) peripheral blood mononuclear cells) and 21% had archived mutations. Usage of a NNRTI-based HAART was the only independent predictor of viral suppression below the cut-off value of the modified ultrasensitive assay. CONCLUSIONS: In our population, NNRTI-based HAART seems to have a stronger impact on residual replication than protease inhibitor-based HAART. This finding may be considered in therapeutic decisions such as the choice of initial HAART regimen and the interruption or simplification of treatment.

Adult↗

PubMed2005

Interleukin-15 enhances the secretion of IFN-gamma and CC chemokines by natural killer cells from HIV viremic and aviremic patients.

Several lines of evidence documented a renewed interest in the role of natural killer (NK) cells in the innate immune control of HIV infection and disease progression. To further assess the role of NK cells as target for immunotherapy in HIV infection, we evaluated the priming effect of interleukin (IL)-15 on freshly isolated human peripheral NK cells, from viremic and aviremic HIV-infected patients, measuring the production of IFN-gamma and CC chemokines. In vitro IL-15 priming induced a significant increase of IFN-gamma production in both viremic and aviremic patients. IL-15 stimulated NK cells producing CC chemokine quantities that are reported to be capable of inhibiting HIV infection and replication. This priming effect is observed both in viral suppressed patients after antiretroviral therapy, and in viremic subjects with progressive HIV infection. The combination of IL-15 plus IL-12 is the most potent costimulus for CD69 expression and production of CC chemokines by NK cells. These findings indicate that NK cells are an important target for immunotherapeutic agents and provide additional pre-clinical data supporting the great potential of IL-15 in the immune-based interventions in HIV disease.

Adult↗

PubMed2005

Association between cellular human immunodeficiency virus DNA level and immunological parameters in patients with undetectable plasma viremia level during highly active antiretroviral therapy.

The association between human immunodeficiency virus (HIV) DNA load and immunologic parameters was investigated in 163 HIV-infected patients with undetectable plasma viremia during highly active antiretroviral therapy (HAART). Patients with HIV DNA below the 25th percentile (133 copies/10(6) peripheral blood mononuclear cells) had higher pre-HAART (P = 0.001) and current (P = 0.005) CD4 counts and a prolonged duration of treatment (P = 0.001). At adjusted analysis, prolonged duration of treatment was independently associated with lower (P = 0.006) and undetectable (P < 0.001) HIV DNA values.

Adult↗

PubMed2003

IFN-alpha promotes the rapid differentiation of monocytes from patients with chronic myeloid leukemia into activated dendritic cells tuned to undergo full maturation after LPS treatment.

Chronic myelogenous leukemia (CML) is a malignant myeloproliferative disease arising from the clonal expansion of a stem cell expressing the bcr/abl oncogene. CML patients frequently respond to treatment with interferon-alpha (IFN-alpha), even though the mechanisms of the response remain unclear. In the present study, we evaluated the role of IFN-alpha in differentiation and activity of monocyte-derived dendritic cells (DCs) from CML patients as well as in modulation of the cell response to lipopolysaccharide (LPS). Treatment of CML monocytes with IFN-alpha and granulocyte-macrophage colony-stimulating factor (GM-CSF) resulted in the rapid generation of activated DCs (CML-IFN-DCs) expressing interleukin-15 (IL-15) and the antiapoptotic bcl-2 gene. These cells were fully competent to induce IFN-gamma production by cocultured autologous T lymphocytes and expansion of CD8(+) T cells. LPS treatment of CML-IFN-DCs, but not of immature DCs generated in the presence of IL-4/GM-CSF, induced the generation of CD8(+) T cells reactive against autologous leukemic CD34(+) cells. Altogether, these results suggest that (1) the generation of highly active monocyte-derived DCs could be important for the induction of an antitumor response in IFN-treated CML patients and (2) IFN-alpha can represent a valuable cytokine for the rapid generation of active monocyte-derived DCs to be utilized for vaccination strategies of CML patients.

Adult↗

PubMed2003

Potent immune response against HIV-1 and protection from virus challenge in hu-PBL-SCID mice immunized with inactivated virus-pulsed dendritic cells generated in the presence of IFN-alpha.

A major challenge of AIDS research is the development of therapeutic vaccine strategies capable of inducing the humoral and cellular arms of the immune responses against HIV-1. In this work, we evaluated the capability of DCs pulsed with aldrithiol-2-inactivated HIV-1 in inducing a protective antiviral human immune response in SCID mice reconstituted with human PBL (hu-PBL-SCID mice). Immunization of hu-PBL-SCID mice with DCs generated after exposure of monocytes to GM-CSF/IFN-alpha (IFN-DCs) and pulsed with inactivated HIV-1 resulted in a marked induction of human anti-HIV-1 antibodies, which was associated with the detection of anti-HIV neutralizing activity in the serum. This vaccination schedule also promoted the generation of a human CD8+ T cell response against HIV-1, as measured by IFN-gamma Elispot analysis. Notably, when the hu-PBL-SCID mice immunized with antigen-pulsed IFN-DCs were infected with HIV-1, inhibition of virus infection was observed as compared with control animals. These results suggest that IFN-DCs pulsed with inactivated HIV-1 can represent a valuable approach of immune intervention in HIV-1-infected patients.

AIDS Vaccines↗

PubMed2003

Monocyte-derived dendritic cells generated after a short-term culture with IFN-alpha and granulocyte-macrophage colony-stimulating factor stimulate a potent Epstein-Barr virus-specific CD8+ T cell response.

Cellular immune responses are crucial for the control of EBV-associated lymphoproliferative diseases. To induce an anti-EBV cell-mediated immunity, we have used dendritic cells (DCs) generated by a 3-day culture of human CD14(+) monocytes in the presence of GM-CSF and type I IFN (IFN-DCs) and pulsed with peptides corresponding to CTL EBV epitopes. The functional activity of IFN-DCs was compared with that of APCs differentiated by culturing monocytes for 3 days with GM-CSF and IL-4 and indicated as IL-4-DCs. Stimulation of PBLs from EBV-seropositive donors with EBV peptide-pulsed autologous IFN-DCs resulted in a stronger expansion of specific T lymphocytes producing IFN-gamma with respect to stimulation with peptide-loaded IL-4-DCs, as assessed by ELISPOT assays. When purified CD8(+) T cells were cocultured with EBV peptide-pulsed IFN-DCs or IL-4-DCs, significantly higher levels of specific cytotoxic activity were observed in CD8(+) T cell cultures stimulated with IFN-DCs. Injection of peptide-pulsed IFN-DCs into SCID mice transplanted with autologous PBLs led to the recovery of a significantly greater number of EBV-specific human CD8(+) T cells from the spleen and the peritoneal cavity with respect to that recovered from mice injected with peptide-pulsed IL-4-DCs. Moreover, a significant delay in lymphoma development was observed when peptide-pulsed IFN-DCs were injected into SCID mice reconstituted with PBMCs endowed with a high capability of lymphoma induction, whereas injection of unpulsed IFN-DCs was ineffective. Our results indicate that IFN-DCs efficiently promote in vitro and in vivo the expansion of CD8(+) T lymphocytes acting as cytotoxic effectors against EBV-transformed cells.

Animals↗

PubMed2003

Vav exchange factor counteracts the HIV-1 Nef-mediated decrease of plasma membrane GM1 and NF-AT activity in T cells.

Several findings support the importance of GM1-enriched lipid microdomains of plasma membrane and of Vav, an essential regulator of actin cytoskeletal rearrangement, in the regulation of T cell activation. Moreover, a functional link among lipid microdomains, Vav and the HIV product Nef has been described. These observations suggest that Nef can modify plasma membrane GM1, affecting the behavior of HIV-infected cells towards antigen recognition and Vav towards counteracting such an effect. We observed that Nef expression, either following viral infection or ectopic expression, significantly decreased the level of plasma membrane GM1 in unstimulated T cells. This down-regulation was associated with the inhibition of NF-AT activation, but not with NF-kappaB activation induced by TCR engagement. Dissecting the signaling pathway that regulates NF-AT activation, we found that Nef inhibited exclusively the Ca(2+)/calcineurin cascade, whereas the JNK cascade and AP-1 transcriptional activity were not affected. Our evidence that Vav overexpression counteracted both the Nef-induced decrease of GM1 expression and the inhibition of NF-AT activity, suggests a novel mechanism by which Nef may interfere with TCR-mediated activation through the modulation of intracellular trafficking and clustering of GM1-enriched microdomains at the cell surface.

Calcium Signaling↗

PubMed2002

Discordant response to antiretroviral therapy: HIV isolation, genotypic mutations, T-cell proliferation and cytokine production.

OBJECTIVE: To study virologic and immunologic factors associated with discordant treatment response in HIV-infected patients receiving highly active antiretroviral therapy (HAART). DESIGN: Study participants included a total of 27 patients: (a) 10 discordant patients (mean CD4+ cell count, 396.1 x 10 cells/l; mean HIV-RNA, 5.4 log copies/ml); (b) seven responder patients (mean CD4+ cell count, 997.5 x 10 cells/l); and (c) 10 failing patients (mean CD4+ cell count 66.5 x 10 cells/l; mean HIV-RNA, 5.4 log copies/ml).(10) (10) METHODS: The HIV-1 isolation rate and biological phenotype, drug resistance genotypic mutations of HIV-1 strains, recall and HIV-1-specific antigen lymphocyte proliferation (LP), and interleukin (IL)-15 production were studied. RESULTS: Virus isolation was obtained in 30% of discordant patients, and in 100% of failing patients. A higher replication constant was reported in discordant patients. No difference in the number of drug resistance mutations and biological phenotypes of HIV-1 was found in discordant patients with respect to failing patients. Discordant patients developed positive LP responses to and HIV-1 p24. LP in response to, HIV-1 p24 and gp160 was positive in responder patients. No significant LP was found in failing patients. Increased levels of IL-15 after stimulation with lipopolysaccaride (LPS) and were found in both discordant patients and responder patients. Conversely, a strong reduction of IL-15 levels was observed in failing patients. CONCLUSION: The present results suggest that decreased virus isolation rate, restoration of both lymphocyte proliferation and IL-15 production are factors involved in the discordant antiretroviral therapy response of HIV-infected patients.

Adult↗