FIG. 3.

(A) Tax-1 is persistently expressed in HTLV-1-infected cultures of astrocytes, at least until 22 and 30 days postinfection (dpi) in rat and human cells, respectively. Tax-1 mRNA was detected in astrocyte cultures after transient contact with HTLV-1-infected T lymphocytes (Southern blotting of RT-PCR products hybridized with a specific internal radiolabeled probe). CyP-A was used as the quality control for RT-PCR. (B) The proinflammatory cytokine TNF-α was secreted following transient treatment of rat and human astrocyte cultures with infected T cells (direct contact or use of insert allowing only soluble factors to diffuse). Note that TNF-α was not detected in control cultures (naive astrocytes and astrocytes transiently exposed to noninfected CD4⁺ T lymphocytes [CEM cell line]. TNF-α was assayed using rat- or human-specific EIA kits.