Maud Santillana-Hayat

Effects of Chemical and Physical Agents on Viability and Infectivity of Encephalitozoon intestinalis Determined by Cell Culture and Flow Cytometry

ABSTRACT We combined tissue culture and flow cytometry to assess the activities of various temperatures, chemicals, and disinfectants on the viability and infectivity of spores of Encephalitozoon intestinalis. Surfanios and benzalkonium chloride, disinfectants currently used in the hospital, were remarkably efficient in destroying spore viability and infectivity.

Anti-Toxoplasma Activities of Antiretroviral Drugs and Interactions with Pyrimethamine and Sulfadiazine In Vitro

ABSTRACT The anti-Toxoplasma activities of nine antiretroviral drugs were examined in vitro. Nucleoside analogs had no effect on parasite growth, whereas ritonavir and nelfinavir were inhibitory for Toxoplasma, with 50% inhibitory concentrations of 5.4 and 4.0 μg/ml, respectively. None of the antiviral drugs affected the anti-Toxoplasmaactivity of pyrimethamine or sulfadiazine.

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.

Studies on in vitro interferon induction capacity and interferon sensitivity of Simian foamy viruses

SummaryWe demonstrate that Simian Foamy viruses (SFV) types 1, 2, 4 and 10 do not induce Interferon (IFN) production in mouse and primate (simian and human) cell lines, but that their cytopathogenic effect is blocked by this viral inhibitor. The mechanisms of action of IFN seems to be different from that of other Retroviridae. No trapping of virions appears in treated cells examined by ectron microscopy. Moreover, neither precursor nor mature virus particles were observed in infected cultures submitted to IFN treatment.

Inhibitory Activity of Human Immunodeficiency Virus Aspartyl Protease Inhibitors against Encephalitozoon intestinalis Evaluated by Cell Culture-Quantitative PCR Assay

ABSTRACT Immune reconstitution might not be the only factor contributing to the low prevalence of microsporidiosis in human immunodeficiency virus (HIV)-infected patients treated with protease inhibitors, as these drugs may exert a direct inhibitory effect against fungi and protozoa. In this study, we developed a cell culture-quantitative PCR assay to quantify Encephalitozoon intestinalis growth in U-373-MG human glioblastoma cells and used this assay to evaluate the activities of six HIV aspartyl protease inhibitors against E. intestinalis. A real-time quantitative PCR assay targeted the E. intestinalis small-subunit rRNA gene. HIV aspartyl protease inhibitors were tested over serial concentrations ranging from 0.2 to 10 mg/liter, with albendazole used as a control. Ritonavir, lopinavir, and saquinavir were able to inhibit E. intestinalis growth, with 50% inhibitory concentrations of 1.5, 2.2, and 4.6 mg/liter, respectively, whereas amprenavir, indinavir, and nelfinavir had no inhibitory effect. Pepstatin A, a reference aspartyl protease inhibitor, could also inhibit E. intestinalis growth, suggesting that HIV protease inhibitors may act through the inhibition of an E. intestinalis-encoded aspartyl protease. These results showed that some HIV protease inhibitors can inhibit E. intestinalis growth at concentrations that are achievable in vivo and that the real-time quantitative PCR assay that we used is a valuable tool for the in vitro assessment of the activities of drugs against E. intestinalis.

Cell transfection with DNA from simian foamy virus type 1 producing cultures generates equivalent infectious virions

Summary The transfection of canine and murine cells with DNA from simian foamy virus type 1 cell cultures led to the appearance of a cytopathic effect (CPE) similar to that induced by the original SFV1. High reverse transcriptase activity was present in supernatants of transfected cultures. Inoculation of these supernatants into permissive cells induced a syncytial CPE and high RNA-dependent DNA polymerase activity. These two effects were specifically inhibited by immune serum against SFV1. By electron microscopy, inoculated cultures showed the presence of virions homologous to those of SFV1.