The IL-2R is composed of three sub-units, α, β, and γ, each of which individually contributes to binding IL-2 in the high affinity IL-2R. The molecular mechanism by which the high affinity IL-2R assembles has not been established. Previous studies have shown that human IL-2R subunits form high affinity hybrid IL-2R when mixed with appropriate mouse IL-2R subunits, but the efficiency of this process is not known. In this study, we produced stable cell lines that expressed hybrid human/mouse IL-2R, comprised of heterologous α- and β-chains, to determine the contribution of individual receptor subunits in stabilizing the high affinity IL-2R. Quantitative ligand binding studies and FACS analysis were performed for EL4J cells that expressed hybrid mouse/human IL-2R, and these data were compared with those of cells that expressed homologous mouse IL-2R subunits. EL4J cells that expressed human β/mouse α formed high affinity IL-2R, comparable with cells that express homologous mouse α and β subunits. In contrast, EL4J cells that expressed homologous mouse IL-2R contained an approximately 10-fold higher level of high affinity IL-2R than did EL4J cells that expressed heterologous human α/mouse β IL-2R. This difference was not accounted for by lower levels of human α-chains in these cell lines or lower expression of the mouse IL-2R β or γ subunits. These results suggest that amino acid sequences within the α subunit, distinct from the IL-2 binding site, are important in the assembly and stabilization of the high affinity IL-2R.
|Original language||English (US)|
|Number of pages||9|
|Journal||Journal of Immunology|
|State||Published - Jan 1 1994|
ASJC Scopus subject areas
- Immunology and Allergy