Infection of peripheral blood mononuclear cells and cell lines by cell-free human T-cell lymphoma/leukemia virus type I.

Previous studies of in vitro infection by human T-cell lymphoma/leukemia virus type I (HTLV-I) have required cocultivation of target cells with HTLV-I cell lines or vesicular stomatitis virus pseudotypes containing HTLV-I envelope proteins. We report here the development of a cell-free infection assay for HTLV-I. Target cells were incubated with purified, DNase-treated HTLV-I virions for 4 h at 37 degrees C. Target cell DNA was then analyzed for the presence of newly synthesized HTLV-I proviral DNA by the highly sensitive polymerase chain reaction. Using this assay system, we have been able to consistently detect in vitro infection of a variety of cellular targets by different HTLV-I isolates. Optimal infection required the presence of 10 micrograms of DEAE-dextran per ml. The assay was dose dependent with respect to virus input. In general, the amount of proviral DNA detected correlated with the level of HTLV-I receptors present on the surface of the target cells, as measured by fluorochrome-labelled HTLV-I binding. Finally, the specificity of the assay was confirmed by demonstrating that the cell line, L1q, a somatic cell hybrid containing human chromosome 17q, to which the gene for the HTLV-I receptor has been mapped, was susceptible to infection by HTLV-I, while the parental mouse cell line from which it was derived, LMTK-, which lacks human chromosome 17q, was not.

Inactivation of human immunodeficiency virus type 1 by ozone in vitro.

A device was designed to deliver a constant source of given concentrations of ozone to fluids containing human immunodeficiency virus type 1 (HIV-1). Ozone was found to inactivate HIV-1 virions in a dose-dependent manner. Greater than 11 log inactivation was achieved within 2 hours at a concentration of 1,200 ppm ozone. Similar concentrations of ozone had minimal effect on factor VIII activity in both plasma and immunoaffinity-purified preparations of factor VIII treated for the same time period. The data indicate that the antiviral effects of ozone include viral particle disruption, reverse transcriptase inactivation, and/or a perturbation of the ability of the virus to bind to its receptor on target cells. Ozone treatment offers promise as a means to inactivate human retroviruses in human body fluids and blood product preparations.

Biology of retroviruses. Detection, molecular biology, and treatment of retroviral infection.

Although human retrovirology can trace its roots to the early part of this century, it has been within the last decade that the field has seen its greatest advances, including the description of the first human retroviruses, HTLV-I, and the subsequent discovery of HTLV-II and the AIDS retroviruses, HIV-1 and HIV-2. The growth this field has undergone in recent years would not have been possible had it not been for key advances in the fields of cell biology, immunology, biochemistry, and molecular biology. Nowhere has this been more evident than in the description of HIV as the etiologic agent of AIDS. In the relatively short time since the disease was initially described, the agent responsible has been isolated, much of its complex biology has been defined, and a drug that helps combat it has been licensed for use. The rapidity with which these events have transpired is largely unprecedented. There remain many unanswered questions regarding HIV and AIDS, and there still is no effective vaccine or cure. Significant questions regarding the immune response to HIV and the HIV response to immune or chemotherapeutic challenge, the establishment and maintenance of HIV latency, and the all-important mechanisms of HIV cytopathicity remain unanswered. It is clear that HIV offers no easy answers, and that significant work remains to be done before death from AIDS can be halted.

Biology of retroviruses: detection, molecular biology, and treatment of retroviral infection.

The general physical characteristics and replication of retroviruses are considered, along with assays for viral products. The specific agent for acquired immunodeficiency syndrome, the human immunodeficiency virus (HIV), is characterized as a lentivirus causing persistent, lifelong infection. While human immunodeficiency virus retroviruses share many of the same properties as other replication-competent viruses, genetic variability occurs among HIV isolates, and this variability may have a considerable effect on the virus' virulence, cell type specificity, viral susceptibility to antiviral compounds, clinical presentation, and disease progression. The most notable difference between HIV replication and other retroviruses is the intricate control of HIV gene expression by viral and cellular factors. Possible mechanisms by which HIV kills infected cells include the formulation of multinucleate syncytia; cytopathic components within the virions themselves; and interaction between viral envelope proteins and the CD4 molecule on the cell surface. Agents shown to inhibit viral replication at the level of the reverse transcriptase are phosphonoformate, sulfated polysaccharides, rifabutin, and nucleoside analogs, as well as purine and pyrimidine analogs. To date, only one nucleoside analog, zidovudine, has demonstrated clear clinical benefit and anti-HIV activity.

Resolution of racemic substances by liquid ion-exchange.

Two optically active liquid anion-exchangers have been synthesized. The separation factors of the enantiomers of sodium (+/-)-mandelate and sodium-N-acetyl-(+/-)-alanate have been determined by batchwise equilibration of aqueous solutions of the salts with chloroform solutions of each of the exchangers. Sodium mandelate has been resolved by Craig countercurrent extraction with one of these exchangers. Optically pure products can be obtained even though the liquid ion-exchanger is not optically pure.