In Vivo Infection of Human T-Cell Leukemia Virus Type I in Non-T Cells

Comparative biology of human T-cell lymphotropic virus type 1 (HTLV-1) and HTLV-2

“…First, cell-free infection by HTLV is very inefficient and efficient infection of cells requires cocultivation of peripheral blood mononuclear cells (PBMC) with irradiated HTLV-producer cells. Secondly, although HTLV has the capacity to infect a number of cell types including T cells, B cells, endothelial cells, glial cells, and monocytes of both human and nonhuman origin (Ho et al, 1984;Hoffman et al, 1984;Akagi et al, 1992;Koyanagi et al, 1993), the only cells susceptible to HTLV transformation are primary T lymphocytes. For the context of this article transformation is defined as continuous growth in the absence of exogenous IL-2; immortalization is defined as continuous IL-2-dependent growth.…”

HTLV-1 tropism and envelope receptor

“…In 1993, Koyanagi et al (1993) thoroughly explored the in vivo infection by HTLV-1 in different hematopoietic cell compartments and in the absence of in vitro culture. Using PCR and RT-PCR to detect Tax DNA and RNA, they demonstrated that although the highest numbers of HTLV-1 DNA proviral copies and active transcription were generally found in CD4 þ T lymphocytes, most asymptomatic HTLV-1-infected individuals, as well as HAM/TSP and ATL patients also exhibited infection of CD8 þ lymphocytes, monocytes and B lymphocytes (Koyanagi et al, 1993) (in vivo infection of nonhematopoietic tissues was not addressed: Y Koyanagi, personal communication). Interestingly, these authors also described an ATL patient in transient remission with no detectable HTLV-1 DNA in CD4 þ cells, even though CD8 þ cells, B cells and monocytes were infected.…”

“…In conclusion, although the CD4 þ T-cell compartment appears to be the overwhelming reservoir, maintaining HTLV-1 infection during the lifespan of an infected individual, other hematopoietic cells (non-CD4 þ T cell subsets, B lymphocytes, monocytes and macrophages, dendritic cells and megakariocytes) as well as glial cells (astrocytes and microglial cells) are also part of the HTLV-1 in vivo tropism (Macatonia et al, 1992;Koyanagi et al, 1993;Lehky et al, 1995;Levin et al, 1997;Eiraku et al, 1998;Hanon et al, 2000;Nagai et al, 2001;Grant et al, 2002).…”

A novel single cell PCR assay: detection of human T lymphotropic virus type I DNA in lymphocytes of patients with adult T cell leukemia

“…[1][2][3] With regard to the in vivo cellular tropism of HTLV-I, it has been reported that HTLV-I infects a variety of hematopoietic cells such as T cells (both CD4-positive and CD8-positive cells), B cells, monocytes and macrophages. [4][5][6] ATL cells have moderately condensed nuclear chromatin and nuclear indentations or lobulations. While the presence of ATL cells is an important pathologic feature of ATL, the proportion of ATL cells in the peripheral blood does not always correspond to the proportion of the malignant cells.…”