Intracytoplasmic detection of the Tac (p55) chain of interleukin-2 receptor in pre-B leukemic cells associated with a constitutive expression of Tac mRNA.
Leukemia
; 4(12): 819-25, 1990 Dec.
Article
en En
| MEDLINE
| ID: mdl-2243505
The pre-B Reh-6 leukemic cells do not express membrane interleukin-2 (IL-2)-R alpha (Tac or p55) chain; however, their incubation with PMA induces the expression of both high and low affinity IL-2-R. Northern analysis of nonstimulated Reh-6 as well as leukemic cells from patients with acute B cell precursor lymphoblastic leukemia displayed a constitutive expression of p55 mRNA transcripts, which could be enhanced by PMA. Both actinomycin-D and cycloheximide could abrogate PMA-induced p55 membrane expression, suggesting the need for de novo mRNA and protein synthesis. The increased PMA-induced p55 mRNA accumulation was an early event (4 hr) and could be enhanced, specifically, by rIL-2 because anti-Tac moAb inhibited this rIL-2-mediated effect. Immunofluorescence and cross-linking studies using 125I-rIL-2 failed to reveal membrane-associated p55 protein on both Reh-6 and patients' leukemic cells. Conversely, immunogold staining and electron microscopy studies, revealed p55 immunoreactive molecules in the cytoplasm but not in the nucleus of all Reh-6 cells. Using a sensitive EIA, p55 molecules could be detected in cell lysates but not the culture supernatants of Reh-6 cells, suggesting that p55 was not released into the culture medium. These results indicate that constitutively expressed p55 mRNA on pre-B leukemic cells is translated into a relative immunoreactive protein that cannot be expressed on cell surface for unknown, yet, reasons.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
ARN Mensajero
/
Leucemia-Linfoma Linfoblástico de Células Precursoras B
/
Receptores de Interleucina-2
/
Expresión Génica
Tipo de estudio:
Diagnostic_studies
/
Risk_factors_studies
Límite:
Humans
Idioma:
En
Revista:
Leukemia
Asunto de la revista:
HEMATOLOGIA
/
NEOPLASIAS
Año:
1990
Tipo del documento:
Article
País de afiliación:
Grecia
Pais de publicación:
Reino Unido