Estudio de la inhibición de la transmisión de la infección de VIH-1 por la nanopartículas de plata recubiertas por polivinilpirrolidona, en un modelo de cultivo de tejido de cérvix humano in vitro

Se ha demostrado que las nanopartículas de plata recubiertas con polivinilpirrolidona (AgNPs-PVP) tienen actividad antiviral contra el VIH-1. Al prevenir la interacción de la gp120 del VIH-1 con el CD4 de la célula huésped, y por consiguiente inhibir la fusión o entrada del virus. En el presente estudio evaluamos la actividad virucida de las AgNPs-PVP , con potencial para prevenir la transmisión de la infección del VIH-1, utilizando un modelo humano in vitro de cultivo cervical. Las AgNPs-PVP de 30-50 nm formuladas en un gel Replens no espermicida a una dosis de 0.15 mg/mL, tienen la capacidad de prevenir la transmisión de la infección tanto del VIH-1 libre de células, como de virus asociados a células, el tiempo mínimo necesario para inhibir la infección fué de un minuto de exposición a las AgNPs-PVP. El pretratamiento por 20 minutos de la biopsia demostró un efecto protector hasta por 48 horas contra la transmisión de la infección por VIH-1. Es importante resaltar el hecho de que las AgNPs-PVP no fueron toxicas para las biopsias aun después de 48 horas de exposició

PVP-coated silver nanoparticles block the transmission of cell-free and cell-associated HIV-1 in human cervical culture

<p>Abstract</p> <p>Background</p> <p>Previous <it>in vitro </it>studies have demonstrated that polyvinylpyrrolidone coated silver nanoparticles (PVP-coated AgNPs) have antiviral activity against HIV-1 at non-cytotoxic concentrations. These particles also demonstrate broad spectrum virucidal activity by preventing the interaction of HIV-1 gp120 and cellular CD4, thereby inhibiting fusion or entry of the virus into the host cell. In this study, we evaluated the antiviral activity of PVP-coated AgNPs as a potential topical vaginal microbicide to prevent transmission of HIV-1 infection using human cervical culture, an <it>in vitro </it>model that simulates <it>in vivo </it>conditions.</p> <p>Results</p> <p>When formulated into a non-spermicidal gel (Replens) at a concentration of 0.15 mg/mL, PVP-coated AgNPs prevented the transmission of cell-associated HIV-1 and cell-free HIV-1 isolates. Importantly, PVP-coated AgNPs were not toxic to the explant, even when the cervical tissues were exposed continuously to 0.15 mg/mL of PVP-coated AgNPs for 48 h. Only 1 min of PVP-coated AgNPs pretreatment to the explant was required to prevent transmission of HIV-1. Pre-treatment of the cervical explant with 0.15 mg/mL PVP-coated AgNPs for 20 min followed by extensive washing prevented the transmission of HIV-1 in this model for 48 h.</p> <p>Conclusions</p> <p>A formulation of PVP-coated AgNPs homogenized in Replens gel acts rapidly to inhibit HIV-1 transmission after 1 min and offers long-lasting protection of the cervical tissue from infection for 48 h, with no evidence of cytotoxicity observed in the explants.</p> <p>Based on this data, PVP-coated AgNPs are a promising microbicidal candidate for use in topical vaginal/cervical agents to prevent HIV-1 transmission, and further research is warranted.</p

Use of silver nanoparticles increased inhibition of cell-associated HIV-1 infection by neutralizing antibodies developed against HIV-1 envelope proteins

<p>Abstract</p> <p>Background</p> <p>HIV/AIDS pandemic is a worldwide public health issue. There is a need for new approaches to develop new antiviral compounds or other therapeutic strategies to limit viral transmission. The envelope glycoproteins gp120 and gp41 of HIV are the main targets for both silver nanoparticles (AgNPs) and neutralizing antibodies. There is an urgency to optimize the efficiency of the neutralizing antibodies (NABs). In this study, we demonstrated that there is an additive effect between the four NABs and AgNPs when combined against cell-associated HIV-1 infection <it>in vitro</it></p> <p>Results</p> <p>Four NABs (Monoclonal antibody to HIV-1 gp41 126-7, HIV-1 gp120 Antiserum PB1 Sub 2, HIV-1 gp120 Antiserum PB1, HIV-1 gp120 Monoclonal Antibody F425 B4e8) with or without AgNPs of 30-50 nm in size were tested against cell free and cell-associated HIV_IIIBvirus. All NABs inhibited HIV-1 cell free infection at a dose response manner, but with AgNPs an antiviral additive effect was not achieved Although there was no inhibition of infection with cell-associated virus by the NABs itself, AgNPs alone were able to inhibit cell associated virus infection and more importantly, when mixed together with NABs they inhibited the HIV-1 cell associated infection in an additive manner.</p> <p>Discussion</p> <p>The most attractive strategies to deal with the HIV problem are the development of a prophylactic vaccine and the development of effective topical vaginal microbicide. For two decades a potent vaccine that inhibits transmission of infection of HIV has been searched. There are vaccines that elicit NABs but none of them has the efficacy to stop transmission of HIV-1 infection. We propose that with the addition of AgNPs, NABs will have an additive effect and become more potent to inhibit cell-associated HIV-1 transmission/infection.</p> <p>Conclusions</p> <p>The addition of AgNPs to NABs has significantly increased the neutralizing potency of NABs in prevention of cell-associated HIV-1 transmission/infection. Further exploration is required to standardize potentiation of NABs by AgNPs. It is also required to evaluate in vivo toxicity of AgNPs before AgNPs could be incorporated in any antiviral vaginal creams.</p

Mode of antiviral action of silver nanoparticles against HIV-1

<p>Abstract</p> <p>Background</p> <p>Silver nanoparticles have proven to exert antiviral activity against HIV-1 at non-cytotoxic concentrations, but the mechanism underlying their HIV-inhibitory activity has not been not fully elucidated. In this study, silver nanoparticles are evaluated to elucidate their mode of antiviral action against HIV-1 using a panel of different <it>in vitro </it>assays.</p> <p>Results</p> <p>Our data suggest that silver nanoparticles exert anti-HIV activity at an early stage of viral replication, most likely as a virucidal agent or as an inhibitor of viral entry. Silver nanoparticles bind to gp120 in a manner that prevents CD4-dependent virion binding, fusion, and infectivity, acting as an effective virucidal agent against cell-free virus (laboratory strains, clinical isolates, T and M tropic strains, and resistant strains) and cell-associated virus. Besides, silver nanoparticles inhibit post-entry stages of the HIV-1 life cycle.</p> <p>Conclusions</p> <p>These properties make them a broad-spectrum agent not prone to inducing resistance that could be used preventively against a wide variety of circulating HIV-1 strains.</p

EL TROPISMO DEL VIH Y SU FENOTIPIFICACIÓN.

El objetivo de nuestra investigación en el BL-3 empieza al enfocarnos para entender las interacciones especificas entre los componentes moleculares del VIH y las proteínas humanas .Este proceso nos definirá cuales son los factores del huésped que son requeridos para una infección productiva. Un objetivo inmediato de esos estudios son el proveer con nuevas terapias para el desarrollo de nuevos medicamentos. Usando lo que hemos conocido sobre estos trabajos moleculares intentamos estudiar las interacciones moleculares del VIH y el sistema inmune del huésped .Palabras clave : Tropismo , HIV, CD4, CXCR4, CCR5, Compuestos Arginino Aminoglicosidos , mutaciones , antiretroviralesTropism, HIV, CD4, CXCR4, CCR5, Arginine aminoglicosid, Mutations, Antiretrovira

Clinical and immunological assessment in breast cancer patients receiving anticancer therapy and bovine dialyzable leukocyte extract as an adjuvant

Dialyzable leukocyte extract (DLE) is one of the immunological agents used as an adjuvant in cancer therapy; it has been associated with improved quality of life during cancer chemotherapy. Based on these previous findings and on the observed clinical benefits attributed to DLE in other types of cancer, we investigated its clinical and immunological effects as a therapy adjuvant on breast cancer patients who received only chemotherapy, as compared to patients administered bovine DLE (bDLE) as an adjuvant. This study included 43 breast cancer patients who were about to begin chemotherapy. This group was divided as follows: 25 received chemotherapy and bDLE as an adjuvant therapy, and 18 received only chemotherapy without the adjuvant. All patient clinical and immunological responses were monitored. Among patients in the group that received bDLE as adjuvant, 60% showed a complete response, 32% showed a partial response and 8% did not respond. By contrast, in the group without the adjuvant, 39% showed a complete response, 50% displayed a partial response and 11% were non-responders. In addition, bDLE treatment in combination with chemotherapy resulted in the enhancement of the Karnofsky performance scale during chemotherapy. Even though patients underwent several cycles of chemotherapy without bDLE, the lymphocyte population dropped to below the reference value. On the other hand, in patients with bDLE as adjuvant, the CD4(+) and CD8(+) lymphocytes and the B lymphocytes were maintained within the median range of the reference value. The number of natural killer cells also increased after chemotherapy treatment with bDLE as an adjuvant. In conclusion, bDLE treatment contributes to significant immunological recovery in patients that have undergone heavy chemotherapy, increasing the clinical response and quality of life during chemotherapy

Antiviral mode of action of bovine dialyzable leukocyte extract against human immunodeficiency virus type 1 infection

<p>Abstract</p> <p>Background</p> <p>Bovine dialyzable leukocyte extract (bDLE) is derived from immune leukocytes obtained from bovine spleen. DLE has demonstrated to reduce transcription of Human Immunodeficiency Virus Type 1 (HIV-1) and inactivate the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling pathway. Therefore, we decided to clarify the mode of antiviral action of bDLE on the inhibition of HIV-1 infection through a panel of antiviral assays.</p> <p>Results</p> <p>The cytotoxicity, HIV-1 inhibition activity, residual infectivity of bDLE in HIV-1, time of addition experiments, fusion inhibition of bDLE for fusogenic cells and the duration of cell protection even after the removal of bDLE were all assessed in order to discover more about the mode of the antiviral action.</p> <p>HIV-1 infectivity was inhibited by bDLE at doses that were not cytotoxic for HeLa-CD4-LTR-β-gal cells. Pretreatment of HIV-1 with bDLE did not decrease the infectivity of these viral particles. Cell-based fusion assays helped to determine if bDLE could inhibit fusion of Env cells against CD4 cells by membrane fusion and this cell-based fusion was inhibited only when CD4 cells were treated with bDLE. Infection was inhibited in 80% compared with the positive (without EDL) at all viral life cycle stages in the time of addition experiments when bDLE was added at different time points. Finally, a cell-protection assay against HIV-1 infection by bDLE was performed after treating host cells with bDLE for 30 minutes and then removing them from treatment. From 0 to 7 hours after the bDLE was completely removed from the extracellular compartment, HIV-1 was then added to the host cells. The bDLE was found to protect the cells from HIV-1 infection, an effect that was retained for several hours.</p> <p>Conclusions</p> <p>bDLE acted as an antiviral compound and prevented host cell infection by HIV-1 at all viral life cycle stages. These cell protection effects lingered for hours after the bDLE was removed. Interestingly, bDLE inhibited fusion of fusogenic cells by acting only on CD4 cells. bDLE had no virucidal effect, but could retain its antiviral effect on target cells after it was removed from the extracellular compartment, protecting the cells from infection for hours.</p> <p>bDLE, which has no reported side effects or toxicity in clinical trials, should therefore be further studied to determine its potential use as a therapeutic agent in HIV-1 infection therapy, in combination with known antiretrovirals.</p

Silver nanoparticles are broad-spectrum bactericidal and virucidal compounds

<p>Abstract</p> <p>The advance in nanotechnology has enabled us to utilize particles in the size of the nanoscale. This has created new therapeutic horizons, and in the case of silver, the currently available data only reveals the surface of the potential benefits and the wide range of applications. Interactions between viral biomolecules and silver nanoparticles suggest that the use of nanosystems may contribute importantly for the enhancement of current prevention of infection and antiviral therapies. Recently, it has been suggested that silver nanoparticles (AgNPs) bind with external membrane of lipid enveloped virus to prevent the infection. Nevertheless, the interaction of AgNPs with viruses is a largely unexplored field. AgNPs has been studied particularly on HIV where it was demonstrated the mechanism of antiviral action of the nanoparticles as well as the inhibition the transmission of HIV-1 infection in human cervix organ culture. This review discusses recent advances in the understanding of the biocidal mechanisms of action of silver Nanoparticles.</p