Analysis of activated T cell infiltrates in rat renal allografts by gamma camera imaging after injection of 123iodine-interleukin 2.
Activated T cells bearing receptors for interleukin 2 (IL-2) play an important role in immunity and in immunopathological processes such as allograft rejection. In order to investigate the presence of activated T cells in lymphocytic infiltrates in transplanted kidneys, we investigated the uptake and retention of radioactivity after an intravenous injection of radioiodinated IL-2 in experimentally transplanted rats. IL-2 was enzyme radiolabelled with 123iodine using a glucose oxidase/lactoperoxidase method and shown to retain specific binding on an IL-2 receptor positive cell line, C58E6. To examine the kinetics of 123iodine-interleukin 2 (123I-IL-2) uptake in vivo, animals that had been transplanted five days previously with allogeneic or syngeneic grafts were injected with 123I-IL-2 and then imaged using an external gamma camera. Radioactivity was measured at time points up to 240 min after intravenous injection of 123I-IL-2. Four groups of animals were examined: allogeneic grafts (n = 7); syngeneic grafts (n = 6); ischaemic native kidneys (n = 5) all following injection with 123I-IL-2; and allogeneic transplants (n = 5) after injection of 123I-lactalbumin, an irrelevant molecule of similar molecular weight to IL-2. The peak radioactivity after injection was measured and the amount of radioactivity retained in the graft at increasing time intervals after injection was expressed as a function of initial peak radioactivity. At four hours after injection of 123I-IL-2, mean retention of activity by rejecting grafts was 77(+/- 2.68)% of peak activity, compared to 45(+/- 6.38)% in syngeneic controls (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)
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Renal Laboratory, United Medical School, Guy's Hospital, London, UK.
Pratt
J R
JR
Dallman
M J
MJ
Sacks
S H
SH
D000818:Animals; D015902:Gamma Cameras; D007376:Interleukin-2 / Q000493:pharmacokinetics*; D007457:Iodine Radioisotopes; D016030:Kidney Transplantation / Q000276:immunology* / Q000473:pathology*; D008213:Lymphocyte Activation; D008297:Male; D051381:Rats; D011917:Rats, Inbred Lew; D015375:Receptors, Interleukin-2 / Q000378:metabolism; D013601:T-Lymphocytes / Q000276:immunology* / Q000473:pathology*; D014184:Transplantation, Homologous; D014185:Transplantation, Isogeneic
D007376:Interleukin-2; D007457:Iodine Radioisotopes; D015375:Receptors, Interleukin-2