Establishment of an IL-2 independent, human T-cell line possessing only the p70 IL-2 receptor

✍ Scribed by Gordon Starkebaum; Thomas P. Loughran JR.; Cory A. Waters; Francis W. Ruscetti

• Publisher: John Wiley and Sons
• Year: 1991
• Tongue: French
• Weight: 985 KB
• Volume: 49
• Category: Article
• ISSN: 0020-7136
• DOI: 10.1002/ijc.2910490218

✦ Synopsis

A continuous cell line was established from the blood of a patient (HH) with an aggressive cutaneous T-cell leukemia/ lymphoma who lacked antibodies to human T lymphotrophic virus, type 1. The immunophenotype of the cultured cells was CD2+, CD3+, CD4+, CD5+, CD8-, DR' and CD25-(Tac, IL-2 receptor a chain). Southern-blot hybridization analysis of 1-cell-receptor p chain DNA demonstrated the same rearrangement in freshly isolated blood cells and cultured cells, indicating that the cell line was derived from the patient's malignant clone. Since cultured T-cells grew in complete medium without added IL-2, we investigated whether HH cells could be producing and responding to IL-2 in an autocrine fashion. However, no IL-2 was detectable in supernatant from the cell line, while antibodies to IL-2, or to the IL-2 receptor Q or f3 chains did not inhibit cell growth. In addition, no mRNA message for IL-2 was detectable in these cells. The results appear to exclude an autocrine IL-2-dependent mechanism of cell growth for this T-cell line. Although cultured HH cells lacked detectable 11-2 receptor a chain, they did show increased proliferation to exogenous IL-2. Binding studies with '251-IL-2 demonstrated an intermediate affinity receptor for IL-2, & = 1.7n~, with 6400 binding sites per cell, suggesting the presence of an IL-2 receptor f3 chain. Consistent with these findings '251-IL-2 cross-linking studies demonstrated a single receptor calculated to be 75kDa. Also, the f3 chain of the IL-2 receptor was detected by immunofluorescence using specific monoclonal antibodies (MAbs). Nanomolar concentrations of an IL-2-diphteria toxin fusion protein inhibited cellular protein synthesis, an effect abrogated by native IL-2. These findings indicate that the IL-2 receptor @chain was functional. This novel mature T-cell line may be useful in studies of IL-2 receptor regulation and in analysis of the mechanism of T-cell leukemogenesis. ~~