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Biomedical subjects

M Canivet

Publications and source records attributed to M Canivet.

63 records · Page 4Linked to original sources

Effects of human recombinant alpha and gamma and of highly purified natural beta interferons on simian Spumavirinae prototype (simian foamy virus 1) multiplication in human cells.

The present study demonstrates the inhibitory effect of human recombinant interferons (r-Hu-IFN) alpha and gamma, and that of highly purified natural human interferon beta on the replication of simian foamy virus type 1 (SFV1) in human AV3-cell cultures. All IFN led to strong inhibition of the SFV1 cytopathic effect. Electron microscopy showed a 70 to 95% decrease in viral particles. Significant inhibition of virus-associated reverse transcriptase activity was found in supernatant fluids of infected IFN-treated cultures. Metabolic labelling of the virus confirmed the inhibition of extracellular release of SFV1. PAGE analysis of immunoprecipitates indicated a reduction in viral-specific protein bands. Altogether, these results indicate that the mechanism of inhibition of Spumavirinae infection by interferon differs from that described for the other Retroviridae, and particularly for types B, C and D viruses. Our data is of therapeutic interest since Spumavirinae have been linked to pathological processes such as de Quervain thyroiditis.

Cell Line↗

In vitro studies on interferon-inducing capacity and sensitivity to IFN of human foamy virus.

We demonstrate in this article that human foamy virus (HFV) fails to induce interferon (IFN) production in two different human tissue culture cell lines: U373-MG and AV3. We also show the effect of human alpha-, beta- and gamma IFN on the multiplication cycle of HFV. Treatment of cells with 100 IU/ml of any IFN led to strong inhibition of an HFV-induced cytopathic effect. This effect was associated with a significant diminution of reverse transcriptase activity in supernatant fluids of IFN-treated infected cultures, and a substantial decrease in viral particle production, as detected by electron microscopy. All these effects were accompanied by strong inhibition of both viral proteins and RNA synthesis, as well as almost total disappearance of free and integrated proviral DNA. In light of our data, human IFN action on HFV seems to be mediated by a mechanism which differs from that observed in the case of other retroviruses (type C and D for instance); however, it evokes that described for HIV.

Animals↗

Transient immunosuppressive effect induced in rabbits and mice by the human spumaretrovirus prototype HFV (human foamy virus).

Spumaviruses (foamy viruses) constitute one of the three retroviral genera isolated from man. Although spumaviruses have not been clearly linked to a given pathology in humans and other infected species, it is well established that they lead in vivo to chronic infections without detectable viral expression. We thought it of interest to investigate certain aspects of the pathology induced in laboratory animals by human foamy virus (HFV). In this work, we demonstrate that HFV infection of rabbits and mice gives rise to a transient immunosuppressive effect, as evaluated in vitro by lymphocyte transformation tests. This phenomenon occurs shortly after viral inoculation, at around 4-5 days, and regresses within thirty days.

Animals↗

Effect of recombinant human alpha A interferon on Visna virus multiplication in acutely infected ovine cells.

We have studied the effects of recombinant human alpha A interferon (IFN) on the multiplication of Visna retrovirus in ovine cells. Pretreatment with IFN followed by continuous IFN treatment, drastically blocked the Visna virus induced cytopathogenic effect and the emergency of neoformed virions. Thus, virus yield and virus dependent reverse transcriptase activity were highly reduced in supernatant fluids. All these effects were accompanied by a strong inhibition of viral protein synthesis. In the light of these data, human IFN action on Visna retrovirus seems to be determined by a mechanism of action distinct from that described in the case of other Retroviridae.

Animals↗

[Production of circulating interferon in human malaria].

The presence of an interferon-like activity inhibiting the cytopathic effect of vesicular stomatitis virus was studied in 216 sera from 100 patients with P. falciparum (67 cases), P. vivax (16), P. ovale (13), P. malariae (4) infections. 87% of patients were found positive on one or more occasions. The prevalence of interferon-like activity was similar in all 4 species. Titers varied between 20 to 320 U/ml and were found to be higher in Europeans experiencing a primary attack of malaria (mean = 72 U/ml) than in subjects from hyperendemic areas of West Africa (mean = 37 U/ml). In patients followed-up either a delayed positivity or an increase of interferon-like activity was found in 60% of cases. High titers were observed up to the 3rd month. The viral inhibitory activity met all criteria for defining interferon. Seroneutralization assays using anti-alpha and anti-gamma interferon antibodies showed in 5 patients that human malaria was associated with the presence of a gamma interferon.

Africa, Western↗

Comparative studies on IL-6 production status in HTLV-1 chronically infected cell lines derived from different HTLV-1 associated pathologies.

We have comparatively studied the qualitative and quantitative status of Interleukin 6 (IL-6) production in several HTLV-1 chronically infected T-cell lines derived from patients suffering either of adult-T-cell leukemia/lymphoma or of tropical spastic paraparesis (TSP). Two other HTLV-1 chronically infected cell lines, coming from healthy seropositive carriers, were also analyzed. Our results demonstrate that, independently of the origin, all these T cell lines, as compared to uninfected HTLV-1 T cell ones, which were always IL-6 non producers, synthesize and yield comparable amounts of IL-6 synthesis, he nosological origin of infecting viral strains does not seem to play a differential role on IL-6 qualitative or quantitative production parameters.

Blotting, Northern↗

Effects of serotonin and melanin on in vitro HIV-1 infection.

In this article, we describe the effect of indoleamines: serotonin (5-HT) and synthetic soluble melanin, on the multiplication of HIV-1 in T4 lymphocytic cell lines. The results show that viral production is increased when infected CEM-11 cells are incubated with 5-HT (10(-7) M and 10(-8) M) for 72 hours, whereas at higher doses (10(-3) M and 10(-4) M), there is an inhibition of viral multiplication. As well, when infected CEM cells were cultured in the presence of 5-HT at 10(-4) M, during 15 days, virus production, syncytia formation and cytolytic effect were drastically inhibited. Melanin also inhibits HIV-1 cytopathic effect on MT-2 cells, without cell toxicity, at concentrations of 0.2-10 micrograms/ml. Syncytium formation and cell lysis were also blocked by melanin at concentrations of 0.1 to 10 micrograms/ml, when uninfected MT-2 cells were mixed with HIV-1 chronically infected CEM-11 cells.

Antiviral Agents↗