Labelling of interleukin-2 (IL-2) with 123-iodine with retention of its capacity to bind to activated lymphocytes.
Human recombinant interleukin-2 (IL-2) was labelled with Iodine-123 using modified Bolton and Hunter method. Separation from free iodine was performed by gel filtration chromatography using a Sephadex G10 column. HPLC analysis of labelled IL-2 showed that 98% of TCA precipitable radioactivity eluted in a single peak. The immunoreactivity of 123I-labelled IL-2 was determined by divert binding using the Fluorescence Activated Cell Sorter (FACS) and by receptor binding assay of IL-2 to activated lymphocytes. To demonstrate in vivo binding to activated lymphocytes, 123I-labelled IL-2 was injected intravenously into a newly diagnosed diabetic BB/Wistar rat. Higher radioactivity was detected in the pancreas and in the lymph nodes of the BB/W rat compared to a normal rat. These preliminary data show that 123I-labelled IL-2 retains its immunoreactivity and capacity to bind to activated lymphocytes both in vitro and in vivo and may be used for in vivo localization of lymphocytic infiltration in Type 1 diabetes.
D000818:Animals; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000276:immunology / Q000378:metabolism*; D007376:Interleukin-2 / Q000276:immunology*; D007457:Iodine Radioisotopes; D051381:Rats; D011913:Rats, Inbred BB; D013601:T-Lymphocytes / Q000378:metabolism*
D007376:Interleukin-2; D007457:Iodine Radioisotopes