FIG. 2.

Correlation of IL-13 upregulation with HTLV-1 Tax synthesis. The impact of Tax on endogenous IL-13 expression in Jurkat T cells and in Tax-immortalized primary human T cells (Tesi) was investigated. (A) Jurkat cells were transfected with a Tax expression plasmid; RNA was reverse transcribed and analyzed by PCR. As an internal standard, β-actin PCRs were performed with the same cDNA. (B) Human T cells transformed with a repressible Tax gene (Tesi) were kept under conditions of induced (Tesi) and repressed (Tesi+Tet) Tax expression. Total RNA was analyzed by Northern blotting with an IL-13-specific probe. C91-PL and StEd, HTLV-1-infected lymphocytes; PBMC + PHA and Jurkat, uninfected T lymphocytes. (C) Tissue culture supernatants of Jurkat, Tesi, and Tesi+Tet cells were subjected to IL-13 ELISA. The results represent the means from three experiments. Error bars show standard deviations.