Development of a radioligand binding assay for interleukin 2 receptor

A stable and reliable interleukin 2 receptor (IL-2R) radioligand binding assay was developed. The peripheral blood mononuclear cells (PBMC) were separated from healthy human blood and cultured in RPMI-1640 with PHA-M for 72 h. The IL-2R in PBMC was analyzed using either multipoint RBA method or single point RBA method. The results of multipoint RBA (n = 6) were that it is high affinity IL-2R, RT = 1125.7 +- 180.4 (x-bar +- s) per cell, Kd (7.060 +- 2.928) x 10-11 mol/L, and for low affinity IL-2R, RT = 12524.5 +- 3816 (x-bar +- s) per cell, Kd = 2.374 +- 0.924) x 10-9 mol/L. The results of single point RBA method (n = 10) were: for high affinity IL-2R, RT = 1180.40 +- 291.8 (x-ray +- s) per cell, and for low affinity IL-2R, RT 12430.1 +- 3161.2 (x-bar +- s) per cell. There was no statistical significance between the results of the two methods. Single point IL-2R RBA is a practical method for estimation of receptor density or PBMC