The use of an HTLV-I-infected human T-cell line (ATH8) in an interleukin-2 bioassay.

Biological interleukin-2 (IL-2) assays require cells that proliferate only in the presence of IL-2. The most often used human cells for this purpose have been phytohaemagglutinin (PHA)-stimulated buffy coat lymphocytes made dependent on IL-2. The results obtained by this T-blast method have not been easily reproducible and/or comparable due to differences in individual buffy coat batches. Murine cytotoxic T-cell lines (CTLL and CTLL-2) have been widely used in human IL-2 assays, but there remains a need for a human cell line. We have developed an IL-2 bioassay, based on the use of a human HTLV-I-infected Th-cell line, ATH8. These cells express IL-2 receptor and are totally dependent on extrinsic IL-2 for proliferation. The results of the ATH8 IL-2 assay were reproducible and comparable to those obtained with successful T-blast assays. ATH8 cells do not require a prolonged culture period before they are suitable for the IL-2 assay as do T-blasts.