Transactivation of human T-cell leukemia virus type 1 by herpes simplex virus type 1

Cell-type-specific trans-activation of herpes simplex virus thymidine kinase promoter by the human T-cell leukemia virus type I Tax protein

The human T-cell leukemia virus type I Tax protein (HTLV-I Tax) is known as a trans-activating factor for a variety of genes, including those of cytokines. Here, we show that Tax is capable of activating the herpes simplex virus thymidine kinase (HSV-TK) promoter in certain mammalian cell lines. In murine NIH 3T3 fibroblasts and human HeLa cells, trans-activation by Tax was remarkably strong, whereas in human chondrocytic HCS-2/8 and monkey kidney Cos-7 cells, the responsiveness of the TK promoter to Tax was poor. Deletion analysis revealed that one of the two previously described Sp1 sites is required for the Tax responsiveness, whereas the CTF binding site is not. The results suggest possible interactions between the oncogenic Tax protein and the viral TK in coinfected cells in vivo. Care should be taken in the context of HTLV-I research, as the HSV-TK promoter has been widely used in molecular biology and gene therapeutics.

Infection and the etiology and pathogenesis of multiple sclerosis

Multiple sclerosis (MS) currently defies clinical and scientific definitions, and carries a prognosis that remains practically unchanged despite many years of intensive research. Although the prevailing dogma is that MS is an immune-mediated condition, it fulfills none of the criteria of an autoimmune disease. On the other hand, there is enough significant data to suggest that infectious agents(s) could be involved in either direct damage to the white matter or induce inflammatory responses that secondarily affect the brain. Our goal here is to review the data supporting the possibility that infection has a critical role in the disease, examine the list of potential candidates that have been suggested, and outline an approach regarding the potential role of infectious agents in the etiology and pathogenesis of MS.

Characterization of retroviruses from patients with multiple sclerosis

These studies were performed to characterize retroviruses found in cell lines spontaneously developed from peripheral blood mononuclear cells (PBMNC) from 6 multiple sclerosis patients, a patient with progressive myelopathy and a healthy control. The cell lines are B-lymphoblastoid and produce Epstein-Barr virus (EBV) particles or express EBV proteins. The B-lymphoblastoid cell lines are also characterized by production of low, fluctuating amounts of retrovirus. The low productivity complicates purification and characterization, but implementation of product-enhanced reverse transcriptase (PERT) assays has provided a highly useful tool for monitoring retrovirus production. By electron microscopy, the retroviral particles appear type-C-like. Functional assays indicate the presence of Pol, Gag and Env. Indirect ELISA demonstrates a significant relation between disease activity and reactivity towards retroviral peptides. Molecular characterization is primarily based on RT-PCR, cloning, sequencing and Northern- or Southern analyses. Molecular characterization is continuing.