Establishment and characterization of 10 cell lines derived from patients with adult T-cell leukemia.

Abstract

By using human T-cell growth factor (TCGF), 10 cell lines were established from tissue samples of 10 patients with adult T-cell leukemia (ATL). Three cell lines were adapted to growth in medium lacking TCGF. The surface markers of all cell lines were characteristic of inducer/helper T cells, i.e., OKT3+, OKT4+, OKT6-, OKT8-, OKIa1+, and human Lyt2+ and Lyt3+, except that one cell line was OKT3-. The expression of the viral antigen was examined during establishment of 8 of the 10 cell lines. The viral antigen was not expressed in leukemic cells before cultivation. In 5 lines, the viral antigen was detected by immunofluorescent staining after a short period of cultivation. However, 3 cell lines, ATL-6A, ATL-9Y, and ATL-1K did not express the viral antigen during short-term culture: the ATL-6A and ATL-9Y cell lines became positive for the viral antigen after 5 and 2 months of cultivation, respectively; the ATL-1K cell line remained antigen-negative throughout a culture period of 13 months. Southern blot hybridization assay showed that all of the cell lines, including the viral antigen-negative ATL-1K cell line, contained the viral genome. Thus, the retrovirus was associated with all 10 cell lines established from ATL patients, but there was a heterogeneity in the expression time of the retroviral antigen in leukemic cells maintained in vitro. Our findings suggested that the expression of the viral antigen was not required for maintenance of the leukemic state in vivo and for growth of leukemic cells in vitro.

Expression of alternatively spliced human T-lymphotropic virus type I pX mRNA in infected cell lines and in primary uncultured cells from patients with adult T-cell leukemia/lymphoma and healthy carriers.

“…The tax gene can also transform NIH 3T3 and Rat-i fibroblasts (6). Previous studies have failed to readily detect HTLV-I antigens (7)(8)(9) and mRNA (10)(11)(12) in the leukemic cells of ATL patients, suggesting that HTLV-I gene expression is not required for the progression to and maintenance of the leukemic state and that the role of the virus may be limited to the induction of polyclonal T-lymphocyte proliferation years to decades before the development of ATL. This proliferation could lead to secondary events, increasing the chance for leukemia, at which stage HTLV-I gene expression would not be necessary (13).…”

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

“…Two HTLV-I-infected cell lines, ATL1K (human) 8 and GP-1 (guinea-pig), 9 were used as a positive control for single cell PCR analyses of HTLV-I. ATL1K cells contain a single copy of HTLV-I proviral DNA per haploid genome.…”

“…ATL1K cells contain a single copy of HTLV-I proviral DNA per haploid genome. 8,10 GP-1 cells possess the multiple copies of HTLV-I proviral genome. 9 Peripheral blood lymphocytes from two patients with ATL (Table 1) were examined.…”

Epigenetic Control and Reintegration of Extrachromosomal Proviral DNA in HL60 Cells Chronically Infected with Human T Cell Leukaemia Virus Type 1

“…The increase of integrated proviruses during culture of HTLV-I-infected cells due to reintegration of the persistent extrachromosomal proviruses is not confined to our experimental system. Adult T cell leukaemia (ATL) cells harbour only a limited number of integrated proviruses , whereas ATL cells adapted to culture in vitro contain multiple copies (Hoshino et al, 1983). We think this increase occurred during the process of adaptation of ATL cells to culture conditions in vitro.…”

“…We think this increase occurred during the process of adaptation of ATL cells to culture conditions in vitro. During the adaptation period, activation of the transcription and expression of the latent HTLV-I proviruses has been reported (Hoshino et al, 1983). It would not be surprising if there was a concomitant appearance of extrachromosomal DNA during this period, and that this then reintegrated into the genome of the established ATL cell lines.…”