Biodistribution of 125I labeled anti-MIF McAb in the skin allograft rejection of mice

Objective: To investigate the production and biodistribution of macrophage migration inhibition factor (MIF) during allograft rejection using 125I labeled anti-MIF monoclonal antibody (McAb). Methods: 1) Anti-MIF McAb (III. D. 9) was radio-iodinated (Na125I) by Iodogen. 2) Skin allografting mice model was established and the rejection was observed and confirmed daily histologically. 3) The radioactivities in various normal tissues and in the skin allografts of model mice at different intervals after transplantation were measured. Results: 1) The allograft rejection period lasted (13.4 ± 2.5) d with a dense macrophage and lymphocyte infiltration. 2) Transplanted mice received injection of 125I labeled anti-MIF McAb the high levels of radioactivities were found from day 1 and 3, then decreased, but it increased greatly from day 10 till day 14, then decreased again; and the transplanted mice received injection of 125I labeled control antibody showed increased radioactivities from day 1 to day 3 and a slight increase during day 10 to 14. No obvious difference in other organs were found between 125I labeled anti-MIF Abs and control Abs injection groups. Conclusions: MIF expression during allograft rejection process shows a highly significant correlation with macrophage and lymphocyte accumulation in the skin grafts. The up-regulation of MIF expression during rejection provides a possible method for radioimmunoimaging of graft rejection