A cDNA clone encoding a product of activated human T lymphocytes

A cDNA cloning approach was used to study the regulation of gene expression in human T lymphocytes upon mitogen stimulation. Poly(A)+ mRNA was prepared from phytohemagglutinin A (PHA) and 12-O-tetradecanoyl phorbol 13-acetate (TPA) activated human T cells and a cDNA clone library was constructed. After screening by colony hybridization with [32P]cDNA probes made from resting and activated T cell mRNA, several clones whose mRNA increased at least 10 to 20-fold upon stimulation were isolated. Northern blot analysis of the mRNA from various cell types using these cDNA clones as probes revealed that one of the cDNA clones, pNC5A, encoded a gene expressed only in PHA and TPA-stimulated human T lymphocytes and in a human neoplastic T cell line HUT102-SH9. Less than 20 copies of this mRNA species per cell was detected in resting human T lymphocytes, B lymphocytes and monocytes and in two other T cell lymphoma lines (CEM and MOLT4), two B lymphoblastoid cell lines (WIL2-729-HF2 and HFB-1), a myeloid cell line (HL60) and a human embryonic lung fibroblast cell line (MRC-5). Hybrid selection translation and sodium dodecyl sulfate/polyacrylamide gel electrophoretic analysis of the translated product indicated that a polypeptide of 30,000 to 32,000 Mr is encoded by this particular cDNA clone. Thus, this cDNA clone may define a novel gene that is expressed only in activated human T cells.