Human T-cell leukemia virus type I (HTLV-I) is a causative agent of neoplastic disease, adult T-cell leukemia (ATL). Although the encoding viral proteins play an important role in oncogenesis, the role of the HTLV-I proviral integration site remains unsolved. We determined the integration sites of HTLV-I proviruses in ATL cells and HTLV-I-infected cells in asymptomatic carriers. In carrier and ...

Human T-cell lymphotropic virus type I (HTLV-I)–associated adult T-cell leukemia/ lymphoma (ATL) is a malignancy of mature activated T cells resistant to conventional chemotherapy. The viral transactivator protein Tax plays a critical role in HTLV-I– induced transformation and apoptosis resistance by inducing IkB-a degradation, resulting in the activation of the NF-kBpathway. In these HTLV-I–tr...

Human T-cell leukemia virus type-I (HTLV-I) is the etiologic agent of adult T-cell leukemia (ATL), an aggressive lymphoproliferative disease. MicroRNAs (miRNAs) are differentially expressed during hematopoiesis and lineage commitment of hematopoietic stem cell progenitors (HSCPs). Here, we report aberrant expression of hematopoietic-specific miR-223, miR-181a, miR-150, miR-142.3p, and miR-155 i...

Human T-cell leukemia virus type-I (HTLV-I), the etiologic agent of adult T-cell leukemia (ATL) transforms human T cells both in vivo and in vitro. However, the long latency period between infection and development of ATL, as well as the small fraction of the infected population that actually develops this disease, suggest that factors in addition to the virus are involved in its pathogenesis. ...

Bovine leukemia virus (BLV) and human T-lymphotropic virus type 1 (HTLV-1) are closely related d-retroviruses that induce hematological diseases. HTLV-1 infects about 15 million people worldwide, mainly in subtropical areas. HTLV-1 induces a wide spectrum of diseases (e.g., HTLV-associated myelopathy/tropical spastic paraparesis) and leukemia/lymphoma (adult T-cell leukemia). Bovine leukemia vi...

Human T-cell leukemia virus type I (HTLV-I) is recognized as the etiologic agent of adult T-cell leukemia (ATL), a disease endemic in certain regions of southeastern Japan, Africa, and the Caribbean basin. Although HTLV-I can immortalize T lymphocytes in culture, factors leading to tumor progression after HTLV-I infection remain elusive. Previous attempts to propagate the ATL tumor cells in ani...

Overexpression of P-glycoprotein (P-gp), the protein product of the multidrug resistance gene (MDR1), confers a drug resistant phenotype on cells. This phenotype is reminiscent of human T-cell leukemia virus (HTLV)-transformed leukemic cells, for which no consistently effective chemotherapeutic regime has been found. The presence of an active multiple drug resistance (MDR) phenotype in freshly ...

Tumaco, Colombia, is an area with elevated rates of tropical spastic paraparesis/human T-cell leukemia virus type I (HTLV-I)-associated myelopathy (TSP/HAM). We have identified a mutation in nucleotide 7959 of the tax gene of 14 Tumaco HTLV-I isolates (14 positive of 14 tested) that was present in 5 of 14 (35%) TSP/HAM patients from Japan and in 8 of 11 (72%) TSP/HAM patients from other geograp...

Little is known about the requirements for human T-cell leukemia virus type I (HTLV-I) entry, including the identity of the cellular receptor(s). Recently, we have generated an HTLV-I surface glycoprotein (SU) immunoadhesin, HTSU-IgG, which binds specifically to cell-surface protein(s) critical for HTLV-I-mediated entry in cell lines. Here, expression of the HTLV-I SU binding protein on primary...

Homologous env sequences from 17 human T-leukemia/lymphotropic virus type I (HTLV-I) strains from throughout the world and from 25 simian T-leukemia/lymphotropic virus type I (STLV-I) strains from 12 simian species in Asia and Africa were analyzed in a phylogenetic context as an approach to resolving the natural history of these related retroviruses. STLV-I exhibited greater overall sequence va...