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Franco Lori

Publications and source records attributed to Franco Lori.

At least 19 recordsLinked to original sources
PubMed2006

Cytokine-adjuvanted HIV-DNA vaccination strategies.

This review highlights some of the most common cytokines currently being tested as adjuvants in HIV-1-DNA vaccine regimens. We discuss their use in both the prophylactic and therapeutic setting. Finally, we describe a novel dendritic cell-targeted vaccine candidate for HIV-1 treatment and prevention called DermaVir and explore the combination of the DermaVir technology with the cytokine adjuvants interleukin-7 and interleukin-15.

AIDS Vaccines↗
PubMed2006

CD4+ T cell-mediated presentation of non-infectious HIV-1 virion antigens to HIV-specific CD8+ T cells.

BACKGROUND: The mechanism of chronic immune activation and impairment of HIV-specific immune responses during chronic infection is not fully understood. However, it is known that high immune activation leads to more rapid progression to AIDS. We hypothesize that CD4(+) T cell-mediated viral antigen presentation contributes to this pathologic immune activation in HIV-infected individuals. METHODS: HIV-specific T cells, responding to noninfectious HIV-1 virions as antigen, were measured by flow cytometric assays. These experimental conditions reflect the in vivo condition where noninfectious HIV-1 represents more than 99% of the antigens. RESULTS: CD4(+) T cells purified from HIV-infected individuals were capable of cross presenting exogenous noninfectious HIV-1 virions to HIV-1-specific CD8(+) T cells. Cross presentation required the entry of HIV-1 to CD4(+) T cells and antigen translocation from endoplasmic reticulum to the Golgi complex. Blocking CD4(+) mediated activation of HIV-specific CD8(+) T cells and redirecting the viral antigens to antigen presenting cells improved HIV-specific T cell responses. CONCLUSIONS: One possible cause of chronic immune activation and impairment of HIV-1 specific T cell responses is represented by HIV-1 harboring CD4(+) T cells cross presenting HIV-1 antigen to activate CD8(+) T cells. This new mechanism provides the first evidence that cross presentation of noninfectious HIV-1 virions play a role in the immunopathogenesis of HIV-1 infection.

Adult↗
PubMed2006

Topical DermaVir vaccine targeting dendritic cells.

DermaVir employs a topical, non-invasive method for vaccine delivery to dendritic cells. The vaccine product contains plasmid DNA as the active ingredient, encoding authentically expressed retroviral genes with appropriate safety modifications. The non-viral delivery system packages the DNA within pathogen-like nanoparticles and studies indicate that vaccine antigens are taken up by epidermal Langerhans cells, the precursors of dendritic cells. DermaVir loaded dendritic cells reach the draining lymph node target but not the bloodstream nor indiscriminately other organ systems. Safety data from DermaVir immunized infected macaques indicate improved survival, absence of apparent toxicities other than transient erythema and lack of recombination between the vaccine DNA and the infectious viral DNA integrated in the host genome. DermaVir represents a potential new approach for the treatment of HIV infection to be utilized either in conjunction with antiretroviral therapy or during structured treatment interruption.

AIDS Vaccines↗
PubMed2005

Optimal suppression of HIV replication by low-dose hydroxyurea through the combination of antiviral and cytostatic ('virostatic') mechanisms.

BACKGROUND: The hydroxyurea-didanosine combination has been shown to limit immune activation (a major pathogenic component of HIV/AIDS) and suppress viral load by both antiviral and cytostatic ('virostatic') activities. Virostatics action represent a novel approach to attack HIV/AIDS from multiple directions; however, the use of these drugs is limited by the lack of understanding of their dose-dependent mechanism of action and by fear of pancreatic toxicity, even though a large review of ACTG studies has shown that hydroxyurea does not increase the incidence of pancreatitis. METHODS: In vitro cytostatic and cytotoxic activity, inhibition of viral replication and immune activation by pharmacologically attainable plasma concentrations of hydroxyurea (10-100 micromol/l) and didanosine (1-5 micromol/l) were analyzed by cell proliferation, viability, apoptosis and infection assays using peripheral blood mononuclear cells. In vivo, 600, 900 and 1200 mg daily doses of hydroxyurea in combination with standard doses of didanosine and stavudine were studied in 115 randomized chronically infected patients. RESULTS: A cytostatic low (10 micromol/l) concentration of hydroxyurea inhibited cell proliferation and HIV replication in vitro. A gradual switch from cytostatic to cytotoxic effects was observed by increasing hydroxyurea concentration to 50-100 micromol/l, predicting that lower doses of hydroxyurea would be less toxic and more potent in vivo. The clinical results confirmed that 600 mg hydroxyurea was better tolerated, had fewer side effects and was more potent in suppressing HIV replication than the higher doses. CONCLUSIONS: A bimodal, dose-dependent, cytostatic-cytotoxic switch is an immune-based mechanism explaining the apparent paradox that lowering the dose of hydroxyurea to 600 mg daily induces maximal antiviral suppression in HIV-infected patients.

Anti-HIV Agents↗
PubMed2005

DermaVir, a novel HIV immunisation technology.

DermaVir is a novel topical immunisation designed to target Langerhans cells (LC), the epidermal precursors of dendritic cells. LC serve as a vehicle to process and transfer antigens from the skin to T cell areas in the lymphoid organs. The HIV DNA delivered by DermaVir to LC expresses most viral regulatory and structural genes and induces T cell-mediated immune responses with broad specificity. In chronically infected macaques, DermaVir administered with antiretroviral drugs, suppressed viral load rebound after treatment interruption and improved survival. DermaVir is a promising antiretroviral treatment approach with a unique mechanism of action for combination with currently used drugs.

AIDS Vaccines↗
PubMed2005

Hydroxyurea exerts a cytostatic but not immunosuppressive effect on T lymphocytes.

OBJECTIVE: To demonstrate that, despite a dose-dependent cytostatic effect, hydroxyurea (HU) does not have immunosuppressive effects. METHODS: The effects of HU on T lymphocyte proliferation parameters, activation phenotype and cytokine production were examined in vitro after exposure to clinically relevant concentrations of HU (10, 50, and 100 micromol/l). The effects of HU in vivo on CD4 T cell counts, viral load, activation phenotype and virus-specific response were examined in 17 Rhesus macaques infected with SIV(mac251) and randomized into three groups: untreated controls; treated with (R)-9-(2-phosphonylmethoxypropyl)adenine (PMPA) and didanosine (ddI) only; and treated with PMPA, didanosine, and HU. RESULTS: The in vitro inhibition of T lymphocyte proliferation confirmed the cytostatic effect of HU, with a linear dose-dependent effect; however, no relevant differences were found in the expression of activation markers between treated and untreated controls. Both T helper type 1 and type 2 cytokine production were enhanced by HU. Consistent with the in vitro results, a blunted increase of peripheral CD4 T cells was observed in vivo in the HU group, without relevant effects on the expression of activation markers, and SIV-specific T cell responses were not affected by HU. CONCLUSIONS: Hyper-proliferation of T-lymphocytes is a major factor contributing to HIV pathogenesis. HU exerts a cytostatic effect on T lymphocytes, without altering their activation and apparently without having an immunosuppressive effect. The increase in cytokine production at the single cell level might compensate for the decrease in the percentage of activated CD4 T lymphocytes, without overall impairment of HIV-specific immune responses.

Animals↗
PubMed2005

Control of viral rebound through therapeutic immunization with DermaVir.

OBJECTIVE: To reconstitute immune responses capable of eliminating infected cells and suppressing viral load during chronic retroviral infection. DESIGN: : A topical, DNA-based therapeutic immunization (DermaVir) was designed to express most of the regulatory and structural viral genes in dendritic cells. METHODS: DermaVir alone and in combination with antiretroviral drugs was tested in chronically SIV-infected macaques. RESULTS: DermaVir provided virological, immunological and clinical benefit for SIV-infected macaques during chronic infection and AIDS. In combination with antiretroviral drugs, DermaVir augmented SIV-specific T-cell responses and enhanced control of viral load rebound during treatment interruptions. CONCLUSIONS: The results indicate the feasibility of therapeutic immunization even in immune compromised hosts, and suggest that DermaVir can complement antiretroviral drugs to sustain suppression of HIV-1 replication.

AIDS Vaccines↗
PubMed2005

Lowering the dose of hydroxyurea minimizes toxicity and maximizes anti-HIV potency.

The goal of this study was to optimize the hydroxyurea dosage in HIV-infected patients, and to minimize the toxicity and maximize the antiviral efficacy of the hydroxyurea-didanosine combination. In a randomized, open-label study (RIGHT 702, a multicenter trial performed in private and institutional practices), three daily doses (600 microg, 800-900 microg, and 1200 microg) of hydroxyurea were administered in combination with didanosine and stavudine to 115 chronically HIV-infected patients, one-third antiretroviral drug naive, with viremia between 5000 and 200,000 copies/ml regardless of CD4+ cell count. The primary efficacy end point was the proportion of patients with plasma HIV-1 RNA levels below 400 copies/ml after 24 weeks of therapy. In the RIGHT 702 intent-to-treat population the lowest (600 mg) dose of hydroxyurea was better tolerated, associated with fewer adverse events, and more potent by all efficacy parameters, including the primary end point (76 versus 60% patients with viremia<400 copies/ml at week 24 for the 600-mg and 800- to 900-mg dose groups, respectively; p=0.027), the mean area under the curve (60.3 versus 65.8; p=0.016), and the mean log10 decrease (-1.95 versus -0.77; p=0.001). Patients receiving 600 mg of hydroxyurea daily also had the highest CD4+ cell count, CD4+/CD8+ cell ratio, and lowest CD8+ cell count and percentage (p=0.035). The RIGHT 702 trial provides an explanation for the increased toxicity and decreased efficacy of hydroxyurea when it was used at high dosage (1200 mg daily). At the optimal dosage of 600 mg daily, hydroxyurea, in combination with didanosine, deserves reevaluation for the long-term management of HIV/AIDS worldwide, because of its excellent resistance profile, durability, and affordability.

Anti-HIV Agents↗
PubMed2005

DermaVir: a novel topical vaccine for HIV/AIDS.

Human immunodeficiency virus (HIV) vaccines have the potential to improve antiretroviral drug treatment by inducing cytotoxic killing of HIV-infected cells. Prophylactic vaccines utilize new antigens to initiate immunity; however, in HIV-infected individuals the load of viral antigen is not the limiting factor for the restoration of immune responses. Here we describe a novel immunization strategy with DermaVir that improves viral antigen presentation using dendritic cells (DC). DermaVir contains a distinctive plasmid DNA expressing all HIV proteins except integrase to induce immune responses with broad specificity. The DNA is formulated to a mannosilated particle to target antigen-presenting cells and to protect the DNA from intracellular degradation. After topical application, DermaVir-transduced cells migrate from the skin to the draining lymph node and interdigitate as DermaVir-expressing, antigen-presenting DC. We compared the immunogenicity of topical and ex vivo DC-based DermaVir vaccinations in naive rhesus macaques. Both vaccinations induced simian immunodeficiency virus-specific CD4 helper and CD8 memory T cells detected by an in vivo skin test and an in vitro intracellular cytokine-based assay. Topical DermaVir vaccination represents an improvement upon existing ex vivo DC-based immunization technologies and may provide a new therapeutic option for HIV-infected patients.

AIDS Vaccines↗
PubMed2004

T-cell receptor excision circles (TREC) in SHIV 89.6p and SIVmac251 models of HIV-1 infection.

T-cell receptor excision circles (TREC) may be a useful surrogate marker in HIV-1 infection for evaluating the likelihood of continued clinical stability and/or the response to therapeutics, including vaccines. Analysis of TREC in SHIV and SIV models of HIV-1 infection may provide additional information concerning the utility of TREC as a marker. We measured TREC in peripheral blood mononuclear cells (PBMC) from rhesus macaques in SHIV89.6p (n = 20) and SIVmac251 (n = 11) models of HIV-1 infection. TREC were also evaluated in tissues in the SIVmac251 model at end-point. In the SHIV89.6p model, TREC in PBMC were significantly lower at 12 weeks postinfection compared to preinfection levels. The decrease in TREC correlated with the decline in CD4+ T cells (r(s) = 0.496; P = 0.026), which in turn correlated inversely with serum viral loads at end-point (r(s) = -0.517; P = 0.019). Macaques that controlled SHIV89.6p infection to some degree (n = 6) had higher TREC at study end-point (P = 0.017). In the SIVmac251 model, TREC in PBMC were significantly reduced after 17 months of infection (P = 0.012) despite receiving highly active antiretroviral therapy (HAART) consisting of didanosine (ddI) and (R)-9-(2-phosphonylmethoxypropyl)-adenine (PMPA) when not cycling off therapy during scheduled treatment interruptions (STI). However, macaques that received continuous hydroxyurea (HU) in addition to the HAART regimen had higher end-point TREC compared to the non-HU group (P = 0.041), and the reduction in TREC observed at end-point within the HU group was not significant. In the SIVmac251 model, TREC correlated with the percentage of CD4+ T cells (r(s) = 0.426; P = 0.048) and CD4+CD28+ T cells (r(s) = 0.624; P = 0.002), and inversely with CD8+ T cells (r(s) = -0.622; P = 0.002), CD8+CD28- T cells (r(s) = -0.516; P = 0.014), and serum viral loads (r(s) = -0.627; P = 0.039). High levels of TREC were observed in the thymus, levels comparable to PBMC were seen in the lymph node, and low but detectable levels of TREC were present in bone marrow. The use of correlates of TREC as covariates in ANCOVA revealed that the decline in TREC in the SHIV 89.6p model reflected the decline in the percentage of CD4+ T-cells due to viral cytopathogenicity. In the SIVmac251 model, the decline in TREC was related to increased immune activation and proliferation due to viral replication, as reflected by decreases in percentages of CD4+CD28+ T cells and increases in CD8+ and CD8+CD28- T cells.

Acquired Immunodeficiency Syndrome↗
PubMed2004

Safety of hydroxyurea in the treatment of HIV infection.

Lifelong adherence to very complex anti-HIV therapy presents drawbacks such as drug resistance and chronic drug-related toxicity, underscoring the need for innovative therapeutic options. As it is becoming increasingly evident that immune activation may be responsible for immune pathology, novel approaches to limit immune activation are under investigation. Hydroxyurea is the prototype of a new family of anti-HIV drugs called virostatics, acting both as an antiviral (directly suppressing HIV) and cytostatic (preventing immune system overactivation). Data from in vitro and clinical studies have proven that hydroxyurea-based regimens are effective options for patients with HIV. However, concerns over hydroxyurea toxicity have limited its use. This review critically examines the role of hydroxyurea for HIV-infected patients, focusing on past and recent clinical trials including the RIGHT 702 study, which identified the safest and most efficacious hydroxyurea dose.

Anti-HIV Agents↗
PubMed2004

APC-targeted immunization for the treatment of HIV-1.

Therapeutic immunization may be thought of as an adjunct to highly active antiretroviral therapy to prime the immune system and possibly correct for immunological defects. Most therapeutic vaccine strategies currently under investigation aim to increase HIV-specific cellular responses. This may be most successfully accomplished by utilizing professional antigen-presenting cells. Autologous dendritic cells may be isolated, cultured, loaded with antigen and re-injected into the subject (ex vivo) or antigen may be directly delivered in situ to Langerhans cells or dermal dendritic cells, which are located respectively at the epidermal and dermal layer of the skin. Once Langerhans cells or dermal dendritic cells have incorporated the antigen, they are expected to mature and migrate to the lymph node to present antigen and stimulate naive T-cells. Exciting results have been obtained in nonhuman primates with both ex vivo and topical antigen-presenting cell-based therapeutic immunization.

AIDS Vaccines↗
PubMed2004

Strategies to decrease viral load rebound, and prevent loss of CD4 and onset of resistance during structured treatment interruptions.

BACKGROUND: Toxicity and other drug adherence-related factors have contributed to decreased compliance to antiretroviral regimens amongst HIV-infected patients. Irregular therapy disruption causes loss of CD4 T cells, onset of drug resistance and rapid rebound of plasma viral load (VL). However, an appropriate choice of drugs and properly scheduled structured treatment interruptions (STIs) may limit VL rebound, maintain CD4 counts and minimize resistance. METHODS: We conducted a clinical study of STIs, RIGHT 901, involving 60 drug-naive patients with chronic HIV infection (CD4 >300, VL >10,000) randomized to receive didanosine-stavudine-indinavir (IDV group) or didanosine-stavudine-hydroxyurea (HU group), for 12 weeks. Subsequently, all patients were randomized again to start STI (short induction) or to continue the therapy for an additional 24 weeks before starting STI (long induction). Both groups underwent four STI cycles and then stopped therapy as long as viraemia remained below 10,000 copies/ml before reinitiating another four cycles of STI. RESULTS: During continuous therapy VLs were suppressed at similar rates in both the HU and IDV groups, while a blunted CD4 count was documented in the HU group. Following the first stop median VL rebounded close to baseline values in both groups, however, during the following STI median VL rebound decreased in the HU group, while in the IDV group VL continued to rebound to values close to baseline, and the difference between the two groups was statistically significant. Moreover, patients treated with HU had a constant and stable CD4 increase during STI, whereas CD4 counts fluctuated in the IDV group, with sharp falls during treatment interruptions and partial CD4 recovery following treatment restart. Even in the presence of IDV resistance predisposing mutations at baseline, no genotypic change in the protease sequence was observed during STI. A relevant mutation in the reverse transcriptase sequence (K70R) emerged in one patient interrupting treatment after 36 weeks of continuous therapy and in one patient after four STI cycles. Side effects (no major events) were similar among groups. CONCLUSIONS: An appropriate choice of STI schedule and regimens containing drugs less prone to resistance and/or able to prevent CD4 fluctuation may contribute to optimizing STI for chronically infected patients with respect to limiting viral rebound, improving CD4 counts and maintaining a resistance profile comparable to continuous highly active antiretroviral therapy.

Anti-HIV Agents↗
PubMed2003

Vaccinia assay for the rapid detection of functional HIV-specific CD8+ cytotoxic T lymphocytes.

Human immunodeficiency virus (HIV)-specific T cells play a critical role in anti-virus immunity. Therefore, during the clinical development of immune-based therapies, it is important to perform a diagnostic test that rapidly quantifies and characterizes cellular immune responses. For detection of functional HIV-specific CD8(+) cytotoxic T cells (CTL), we used a rapid vaccinia assay that employs recombinant vaccinia virus-infected peripheral blood mononuclear cells (PBMC). This assay was compared with the traditional 51Cr-release CTL assay and with the peptide pool-based enzyme-linked immunospot assay (ELISPOT). We demonstrated a close correlation between these assays by using identical antigens in parallel assays. However, the vaccinia assay was the least expensive and time- and labor-consuming test. Regarding sensitivity, the vaccinia assay was similar to both the peptide pool-based ELISPOT and CTL assays. We showed that human histocompatibility leukocyte antigen (HLA)-Dr(+) cells are responsible for presenting recombinant vaccinia antigens to T cells. The recombinant vaccinia-based assay is a rapid, sensitive and quantitative test and is thus suitable for the detection of functional antigen-specific CD8(+) CTL in large-scale clinical studies.

Antigen-Presenting Cells↗
PubMed2003

Therapeutic vaccination for future management of HIV/AIDS.

The investigation of novel and innovative treatment approaches for long-term management of HIV-infection has intensified due to the growing number of infected individuals worldwide and the constraints of resistance, toxicity and inconvenience associated with lifelong therapy. Current treatment relies entirely on antiretroviral drugs targeting various stages of the life cycle of HIV, rather than on leveraging the immune system. However, the boosting of HIV-specific immune responses in chronic infection offers a vast potential for synergy with antiretroviral drugs, thereby contributing to durable control of viral replication. A novel immunotherapeutic agent that delivers plasmid DNA to dendritic cells after topical skin application is the first therapeutic vaccine that has demonstrated immunological and clinical benefit in chronically infected rhesus macaques in combination with antiretroviral therapy.

AIDS Vaccines↗
PubMed2003

A cytostatic drug improves control of HIV-1 replication during structured treatment interruptions: a randomized study.

OBJECTIVE: To study the effect of highly active antiretroviral therapy (HAART) with and without hydroxyurea (HU) on changes in plasma viral load (VL) set-point, and on HIV-1-specific responses, after five cycles of structured treatment interruptions (STI). METHODS: A group of 20 patients taking HAART for chronic HIV infection with VL < 20 copies/ml were randomized to continue HAART or HAART plus HU for 24 weeks followed by five STI cycles. HU was also stopped in cycles 1-3 but continued in cycles 4 and 5. The number of individuals maintaining a VL set-point < 5000 copies/ml during the fifth interruption were determined. RESULTS: VL remained < 5000 copies/ml in eight out of nine patients in the HU group and in four out of ten patients in the HAART group after a median 48 weeks of follow-up after the fifth interruption ( P=0.039). By STI cycle 5, there was a significant increase in the neutralizing activity (NA), in both magnitude and breadth of the total cytotoxic T lymphocyte (CTL) response and in lymphoproliferative response (LPR) from baseline. No significant differences were observed between HAART and HU groups in NA, CTL and LPR at any time-point. There were no differences in the NA titers at any time-point between responder and non-responder patients. There was a trend for higher CTL and LPR levels in responder patients (P= 0.10). CONCLUSIONS: In this randomized, controlled study of STI with cycles of HAART or HAART plus HU, a lower peak VL rebound and a lower VL set-point was achieved in patients continuing HU while other drugs were discontinued. HU did not blunt anti-HIV-1-specific responses; however, control of VL did not correlate with anti-HIV-1-specific cellular immune responses.

Adult↗
PubMed2003

2nd International Symposium on Molecular Diagnostics and Skin Gene Therapy.

The 2nd International Symposium on Molecular Diagnostics and Skin Gene Therapy was held on a beautiful spring weekend at one of the youngest universities in the world, the Heinrich-Heine University, founded 1965. The conference attracted more than 340 participants from 24 different countries, including ethicists, basic researchers, virologists, immunologists, molecular biologists and clinicians, as well as numerous students. The event was organised under the auspices of the European Gene Therapy Society by U Hengge of the Department of Dermatology at Heinrich-Heine University. As Dr J Glorioso, President of the American Society for Gene Therapy, pointed out in his welcome address, the skin is a new target for gene therapy, with the potential for in vivo gene transfer to the central nervous system or to the lymphoid organs, for example. As such, Düsseldorf was a perfect location for such a meeting, because the most important biomedical research investments in Germany have been in neurology and dermatology. Many scientific challenges facing this young field of medicine were presented, but there was also much discussion of ethical, regulatory and safety issues with respect to gene therapy.

Clinical Laboratory Techniques↗