Human T-cell lymphotropic virus 1 and 2 (HTLV-1, HTLV-2) belong to the Retroviridae family, genus Deltaretrovirus1,2 and have similar biological properties, with tropism of T lymphocytes. They are associated with rare lymphoproliferative diseases.3,4 Brazil has a high seroprevalence of HTLV-1/2 among blood donors. The mean prevalence ranges from 0.4/1000 in Florianópolis to 10.0/1000 in São Luí...

Human T-cell leukemia virus type 1 (HTLV-1) causes adult T-cell leukemia (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis in small subsets of HTLV-1 carriers. HTLV-1-specific T-cell responses play critical roles in anti-viral and anti-tumor host defense during HTLV-1 infections. Some HTLV-1 carriers exhibit selective loss or anergy of HTLV-1-specific T-cells at an asymptomati...

INTRODUCTION Human T-lymphotropic virus type 1 and 2 (HTLV-1/2) is endemic in Brazil, but few studies have investigated the seroprevalence of HTLV and its subtypes among blood donors in the capital city Manaus, Amazonas State, Brazil. AIM To estimate the seroprevalence of HTLV-1/2 and to identify circulating subtypes among blood donors in Manaus. MATERIALS AND METHODS Blood donors (2001-200...

In countries with a low prevalence of human T-lymphotropic virus (HTLV) infection, indeterminate HTLV serologies are a major problem in blood bank screening because of the uncertainties about infection in these cases. The recent discovery of two new types of simian T-lymphotropic viruses (STLV), which give an HTLV-indeterminate serology, raises the question whether indeterminate serologies in h...

Human T cell leukemia virus type I (HTLV-I) is a retrovirus that is not lysed by human serum or complement. It has not been determined, however, whether HTLV-I directly binds to complement components or whether it retains infectivity after incubation with human serum. We investigated the effects of human serum on the infectivity of cell-free HTLV-I produced by human and animal cells. Plating of...

Epidemiological studies conducted in Peru disclosed HTLV-1 to be prevalent in different ethnic groups, and found HTLV-2 in some Amazonian Indians and in men who have sex with men. No data concerning HTLV-1/2 infection in blood donors from Arequipa, a highlands region in southern Peru, is available. We searched for the presence of HTLV-1 and HTLV-2 antibodies in 2,732 serum samples obtained from...

Ten human monoclonal antibodies derived from peripheral B cells of a patient with human T-cell lymphotropic virus (HTLV)-associated myelopathy are described. One monoclonal antibody recognized a linear epitope within the carboxy-terminal 43 amino acids of HTLV gp21, and two monoclonal antibodies recognized linear epitopes within HTLV type 1 (HTLV-1) gp46. The remaining seven monoclonal antibodi...

Human T lymphotropic virus type 1 (HTLV-1) is one of the most intriguing retroviruses infecting humans. Most commonly, infection remains undetected, since it does not cause obvious harm, yet in 4-9% of patients, this infection can be devastating, causing adult T-cell leukemia/lymphoma and/or HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP). This review concentrates on all inf...

Human T cell leukemia virus type 1 (HTLV-1) is the causative agent of adult T cell leukemia (ATL) and HTLV-1 - associated myelopathy and tropical spastic paraparesis (HAM/TSP). HTLV-1 has a preferential tropism for CD4 T cells in healthy carriers and ATL patients, while both CD4 and CD8 T cells serve as viral reservoirs in HAM/TSP patients. HTLV-1 has also been detected other cell types, includ...

Human T-cell leukemia virus type 1 (HTLV-1) persistently infects humans, and the proviral loads that persist in vivo vary widely among individuals. Elevation in the proviral load is associated with serious HTLV-1-mediated diseases, such as adult T-cell leukemia and HTLV-1-associated myelopathy/tropical spastic paraparesis. However, it remains controversial whether HTLV-1-specific T-cell immunit...