Cloned lines on interleukin 2 producer human T lymphocytes.

This is the authors' abstract. We don't add key points for this paper.

Cloned lines of human T cells have been developed from the peripheral blood of normal volunteers. The studies reported here were performed with two subclones, each derived from a distinct individual, designated RP1aa and CF2a3, respectively. Both T cell clones have the phenotype OKT3+,4+,8–, HLA-DR+ as determined by indirect immunofluorescence microscopy. RP1aa and CF2a3 cells produced no interleukin 2 (IL 2) constitutively, but they could do so after stimulation with concanavalin A, phorbol myristate acetate, phytohemag-glutinin, and the OKT3 monoclonal anti-human T cell antibody. The IL 2 activity of the supernatants from activated RP1 aa and CF2a3 cells was determined in three distinct assays, namely, support of growth of IL 2 addicted T cells, promotion of lectin-initiated DNA synthesis of thymocytes, and help to thymocytes to express cytotoxicity against allogeneic target cells. In addition, the helper activity was absorbed by IL 2-reactive T cells and not by Epstein Barr virus-transformed B cells. Furthermore, the helper factor(s) responsible for the above biologic effects had apparently 14,000 to 30,000 m.w., determined by Sephadex G-100 chromatography, and its biologic effects were stable at pH 2.0 to 8.0, resistant to temperature of 56°C for 1 hr, and sensitive to trypsin. Neither RP1aa nor CF2a3 cells proliferated to IL 2, IL 1, or γ-interferon and they could not absorb IL 2, indicating these IL 2 producer T cells lack receptors for IL 2. Both RP1aa and CF2a3 cells obtained at week 10 of culture proliferated to purified IL 3 stimulation. After the first 3 mo of culture, RP1aa and CF2a3 cells could grow in the absence of exogenous factors or filler cells and they have been maintained in culture, under these conditions, for 11 ½ months. These observations suggest the growth factor for IL 2 producer cells is something other than IL 2, possibly IL 3 or a factor that copurifies with it. In addition, the data suggest that RP1aa and CF2a3 cells might be supporting their growth by spontaneously secreting their own growth factor. Finally, both RP1aa and CF2a3 cells assisted macrophages, obtained from either peripheral blood of normal human donors or from the murine tumor cell line P388D1, to synthesize IL 1 under the stimulus of the OKT3 monoclonal anti-human T cell antibody or concanavalin A. Thus, RP1aa and CF2a3 lymphocytes, which produce IL 2, can also help macrophages to secrete IL 1.