In order to detect and identify dengue serotypes in serum samples, we developed a single-step quantitative reverse transcription-polymerase chain reaction (Q-RT-PCR) assay (referred to as Q-PCR). Sets of primers were selected from the capsid region of the viral genome. Dengue serotypes 1/3 and 2/4 were detected in two separate duplex amplification reactions using specific primers and fluorogenic TaqMan probes.
View Article and Find Full Text PDFWe have established a stable, continuous culture Drosophila Schneider 2 cell line that efficiently expresses a secreted, truncated form of the HIV envelope gp120 protein in a regulated manner. The Drosophila produced recombinant gp120 protein is highly glycosylated, is recognized by gp120-specific monoclonal antibodies, binds to the CD4 receptor and has the ability to inhibit syncytia formation between uninfected CD4+ cells and HIV infected cells. We conclude that this recombinant Drosophila envelope protein is an appropriate mimic of the authentic viral envelope protein.
View Article and Find Full Text PDFSera, from HIV-1 and HIV-2 seropositive individuals, were tested for the presence of antibodies able to inhibit the binding (BI) of HIV-IIIB gp 160 (produced in mammalian cells using a vaccinia expression system) to the extracellular portion of the CD4 receptor. A competition enzyme immunoassay (EIA) with soluble CD4 (sCD4) was used. BI antibodies were highly prevalent among HIV-1 seropositives but not in HIV-2 infected individuals.
View Article and Find Full Text PDFMouse mAb reactive to the HIV-1 envelope glycoprotein precursor gp160 of the HTLVIII(B) isolate were characterized in radioimmunoprecipitation and immunoblot tests with the use of HTLVIII(B) isolate as Ag. The reactivities of these mAb were also measured in a capture enzyme immunoassay and in radioimmunoprecipitation assay by using gp160 and gp120 expressed as vaccinia recombinants. Striking differences in exposure of specific epitopes were noted between the gp120 component of the gp160 precursor and the fully processed gp120 in both tests.
View Article and Find Full Text PDFRecent studies indicate that human immunodeficiency virus type 1 (HIV) gene expression can be dramatically enhanced by certain heterologous viral and chemical agents, implicating these as potential reactivating agents of latent virus infection. A common denominator shared by these agents is their ability to cause stress responses in cells. In an effort to determine whether stress responses affect HIV gene expression, we examined the effects of ultraviolet light (UV) and mitomycin C, on HIV gene expression as well as on viral growth and development.
View Article and Find Full Text PDFRat hepatoma cells that do not synthesize the hepatic enzyme ornithine carbamoyl transferase spontaneously give rise to producing cells at a low frequency. Reexpression of this differentiation trait is strongly increased by 5-azacytidine treatment, suggesting that hypermethylation plays a critical role in the impaired expression of the ornithine carbamoyl transferase gene in hepatoma cells.
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