(3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assays showed a lack of toxicity of ganciclovir (GCV), C.OXTs, and their derivatives, to TaY(OK) cells at 1 microM. Therefore we compared the antiviral potencies of these drugs at 1 microM by monitoring the viral loads produced during a 1-day period during the course of the drug treatment. Among the drugs tested, 3'-fluorocarbocyclic oxetanocin A (3'F-C.OXT-A) was the most effective for inhibiting the virus production, and at concentrations ranging from 0.5 microM to 10 microM, the inhibition of the viral production was dose-dependent. A comparison of the chemical structures of the derivatives with that of C.OXT-A, which is the parental molecule, suggested that the 3'-fluorine-modification might account for the higher anti-HHV-6 activity and lower cytotoxicity

Estimating immunoregulatory gene networks in human herpesvirus type 6-infected T cells

The immune response to viral infection involves complex network of dynamic gene and protein interactions. We present here the dynamic gene network of the host immune response during human herpesvirus type 6 (HHV-6) infection in an adult T-cell leukemia cell line. Using a pathway-focused oligonucleotide DNA microarray, we found a possible association between chemokine genes regulating Th1/Th2 balance and genes regulating T-cell proliferation during HHV-6B infection. Gene network analysis using an integrated comprehensive workbench, VoyaGene, revealed that a gene encoding a TEC-family kinase, ITK, might be a putative modulator in the host immune response against HHV-6B infection. We conclude that Th2-dominated inflammatory reaction in host cells may play an important role in HHV-6B-infected T cells, thereby suggesting the possibility that ITK might be a therapeutic target in diseases related to dysregulation of Th1/Th2 balance. This study describes a novel approach to find genes related with the complex host-virus interaction using microarray data employing the Bayesian statistical framework.

Transcriptional profiling of human herpesvirus type B (HHV-6B) in an adult T cell leukemia cell line as in vitro model for persistent infection

Human herpesvirus 6 (HHV-6), which is present in more than 90% of the human, is known to cause infectious diseases in immuno-compromised patients, e.g., transplant patients. To clarify the possible role of the pattern of expression of HHV-6 genes in various types of HHV-6B infection, we sought to determine whether or not viral DNA microarray could be used for detailed characterization of viral transcription using a HHV-6B DNA microarray that contains 97 known open reading frames of HHV-6B. A subset of genes are preferentially expressed in persistent infection: U16 (IE-B, transactivator, US22 gene family), U18 (IE-B, homolog to HCMV IE glycoprotein), U20 (glycoprotein), U27 (DNA polymerase processivity transactivator), U82 (gL, gH accessory protein), U83 (chemokine), U85 (OX-2 homology, glycoprotein), U90 (IE-A), and U94 (transactivator), respectively. Although the function of each HHV-6B is not fully understood, our study suggests that comprehensive analysis of HHV-6B transcription is useful not only to clarify the pathogenesis of the virus but also to develop new strategies for anti-viral drugs.

Real-time PCR as a versatile tool for investigating the susceptibility of human herpesvirus 6 to antiviral agents

A quantitative real-time PCR assay was developed for the determination of antiviral drug susceptibility and growth kinetics of human herpesvirus 6. The susceptibility and fitness of a sensitive strain, HST, and its ganciclovir-resistant derivative, GCVR1, were then characterized, leading us to conclude that the mutations of this latter virus did not alter its fitness significantly.