Analysis of interleukin 2 receptor sites on activated T cells

Earlier work has shown that upon polyclonal or antigen-specific activation murine T cells become susceptable to the affect of the T helper cell product Interleukin 2 (IL-2) leading to clonal expansion of activated T cells. It has been suggested that T-cells, as a result of mitogenic or antigenic triggering, express on their surface receptor sites for IL-2. The aim of the present investigation was to analyse the putative IL-2 receptors by quantitative absorption studies. The following results were obtained: activated T cells, triggered by cell antigen or Con A as well as cells of a CTL-clone, but neither LPS-activated B cells nor tumour cells absorbed IL-2; IL-2 was absorbed in a doses dependent fashion until saturation of the absorbing cells; IL-2 absorption occurred within minutes and was temperature-dependent; data comparing activated T cells versus gluteraldehyde-treated activated T cells in repeating absorptions suggested that with gluteraldehyde-treated cells only absorption of IL-2 by the exposed IL-2 receptors is measured, while metabolically active cells seem to assay, besides of the mere binding of IL-2, also an enzymatic event, which probably follows binding of IL-2 to its receptor. The capacity to absorb IL-2 was trypsin-sensitive but insensitive to treatment with neuraminidase.