Radionuclide Imaging of Experimental Atherosclerosis with Nonspecific Polyclonal Immunoglobulin G

The utility of nonspecific polyclonal IgG for external imaging of experimental atherosclerosis was tested in a series of rabbits after balloon catheter deendothelialization of the abdominal aorta. Following injection of /sup 111/In-IgG, /sup 111/In-Fc, or /sup 111/In-Fab serial images were recorded. In addition, several animals received /sup 125/I-low density lipoproteins (/sup 125/I-LDL), or /sup 125/I human serum albumin (/sup 125/I-HSA) as positive and negative controls. Forty-eight hours after injection of the radiolabeled proteins, the aortas were removed, divided into abdominal and thoracic regions, counted, and autoradiographed. The images acquired after injection of /sup 111/In-IgG and /sup 111/In-Fc, showed clear focal accumulation of radioactivity in the healing abdominal aorta. In contrast, the images obtained after injection of /sup 111/In-Fab did not show focal radionuclide accumulation. For /sup 111/In-IgG and /sup 111/In-Fc there were three to six times as many counts in the abdominal as in the thoracic aorta, while for /sup 111/In-Fab and /sup 125/I HSA, the abdominal and thoracic counts were nearly equal. The results suggest that radiolabeled IgG and Fc can be used to image experimental atherosclerosis.