Detection of activated lymphocytes in endocrine pancreas of BB/W rats by injection of 123I-interleukin-2: an early sign of type 1 diabetes.
Recombinant interleukin-2 (IL2) was labelled with iodine-123 by a modified chloramine T method. The labelled IL2, which had a high specific activity (100-150 microCi/microgram) and retained its capacity for binding to the IL2 receptor on activated lymphocytes in vitro, was injected intravenously into BB/W diabetes-prone and normal rats. Combined immunoperoxidase staining and autoradiography of organ sections revealed that labelled IL2 bound specifically in vivo to IL2-receptor-positive cells in the spleen of both normal and BB/W rats and to activated lymphocytes infiltrating the pancreas of BB/W rats. The severity of lymphocytic infiltration correlated with the degree of radioactivity in the pancreas of BB/W rats. Time-activity curves, generated over organs of injected rats after gamma camera imaging, confirmed that radioactivity was greater in the pancreas of diabetes-prone than in normal rats. 123I is a suitable isotope for gamma camera imaging, so the intravenous injection of IL2 labelled with iodine-123 may be valuable for the in-vivo visualisation of activated lymphocytes in tissues infiltrated by lymphocytes.
D000818:Animals; D001345:Autoradiography; D003922:Diabetes Mellitus, Type 1 / Q000473:pathology*; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D066298:In Vitro Techniques; D007275:Injections, Intravenous; D007376:Interleukin-2; D007457:Iodine Radioisotopes; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000032:analysis / Q000473:pathology*; D008297:Male; D010179:Pancreas / Q000473:pathology*; D051381:Rats; D011919:Rats, Inbred Strains; D011971:Receptors, Immunologic / Q000032:analysis; D015375:Receptors, Interleukin-2; D011994:Recombinant Proteins; D013154:Spleen / Q000473:pathology
D007376:Interleukin-2; D007457:Iodine Radioisotopes; D011971:Receptors, Immunologic; D015375:Receptors, Interleukin-2; D011994:Recombinant Proteins