Properties of human interleukin-2 receptors expressed on non-lymphoid cells by cDNA transfection

Abstract

We have established non-lymphoid cell lines HeLa, Ltk and NIH3T3 expressing the human interleukin-2 (IL-2) receptor by transfection of human IL-2 receptor complementary DNA. While IL-2 receptors on T cells are classified into the high and low affinity species, the receptors expressed on the cDNA-transfected non-lymphoid cells belong to the low affinity species. These IL-2 receptors could not transmit the growth signal although they were similar in size to those expressed on T cells. Phorbol ester-induced phosphorylation of the IL-2 receptors on HeLa cells did not affect the affinity of the receptor. We have also constructed a cDNA encoding a mutant IL-2 receptor that replaced the major phosphorylation site, the serine residue at position 247 with the glycine residue. This mutant IL-2 receptor expressed on non-lymphoid cells also had the low affinity for IL-2. The results indicate that the high and low affinity states of the IL-2 receptor are not solely determined by phosphorylation of the receptor. The IL-2 receptors expressed on these non-lymphoid cells were internalized four to eight times more slowly than those on T cells. Possible defects of the IL-2 receptors expressed on non-lymphoid cells are discussed.