title: In vivo localization of radioiodinated peanut lectin in a murine TA3/Ha mammary carcinoma model.
abstract: Peanut lectin (PNA) binds avidly to oligosaccharides containing the terminal sequence beta-D-Gal(1----3)alpha-D-GAlNAc. This disaccharide is the immunodeterminant group of the Thomsen-Friedenreich (T) antigen which is present in an exposed form on a number of human and animal adenocarcinomas and can be identified in tumor tissue sections by histochemical PNA staining techniques. We have studied the in vivo uptake of radioiodinated PNA in a murine TA3/Ha mammary adenocarcinoma model to evaluate the potential applications of radiolabeled PNA for the immunodetection of T antigen expressing carcinoma. We have found that PNA has a high in vitro binding affinity for the TA3/Ha tumor cells as well as for epiglycanin, a glycoprotein fraction shed by the TA3/Ha cells. Tissue biodistribution studies after IV 125I-PNA injection into TA3/Ha tumor-bearing mice indicated tumor:blood ratios of 7:1 and 55:1 at 24 and 48 h with corresponding tumor:muscle ratios of 33:1 and 77:1. The high tumor uptake and rapid blood clearance allowed clear scintigraphic delineation of tumor by 24 and 48 h without the necessity for background subtraction techniques. Rapid in vivo deiodination of 125I-PNA also contributed to localization of radioactivity in the stomach, salivary glands, thyroid, and kidney.
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging*; D000818:Animals; D015295:Antigens, Tumor-Associated, Carbohydrate / Q000032:analysis; D006023:Glycoproteins / Q000378:metabolism; D007457:Iodine Radioisotopes / Q000378:metabolism; D037102:Lectins / Q000378:metabolism; D008297:Male; D008325:Mammary Neoplasms, Experimental / Q000000981:diagnostic imaging*; D008657:Metabolic Clearance Rate; D051379:Mice; D008815:Mice, Inbred Strains; D009368:Neoplasm Transplantation; D019887:Peanut Agglutinin; D011877:Radionuclide Imaging; D011975:Receptors, Mitogen / Q000378:metabolism; D014018:Tissue Distribution
chemical_list: D015295:Antigens, Tumor-Associated, Carbohydrate; D006023:Glycoproteins; D007457:Iodine Radioisotopes; D037102:Lectins; D019887:Peanut Agglutinin; D011975:Receptors, Mitogen; C038223:peanut agglutinin receptor; C016467:Thomsen-Friedenreich antigen