Localization of I131-Labeled Antirat Lymph Node and Kidney Rabbit Antibodies in the Rat

Summary and Conclusions A homogenate of rat lymph node was injected into rabbits to stimulate production of antirat lymph node antibodies. The rabbit globulin was radioiodinated and adsorbed on and eluted from rat lymph node homogenate. The product was tested in vitro by precipitation tests against various organ homogenates, and radioassays showed the presence of labeled antilymph node antibodies. The data from the rats injected subcutaneously and serially sacrificed showed the presence of labeled antibodies which localized in lymph nodes more than did labeled antikidney antibodies or labeled globulin from normal serum. Labeled antilymph node antibodies localized in spleen and mesenteric lymph nodes more than did labeled antikidney antibodies or labeled globulin from normal serum. In this experiment, antibodies prepared against lymphatic tissue differed qualitatively from other proteins in their lymphatic tissue localization. An alternative method of preparation was employed in which antibody separation was followed, rather than preceded, by isotope labeling. Antibodies so labeled were injected intravenously and subcutaneously for an in vivo test similar to the previous experiment. Intravenous injection resulted in maximum antibody localization in spleen. Subcutaneous injection resulted in maximum antibody localization (up to 25% of the significant dose) at the injection site and the lymph nodes which drained it. As is well known, lymphatic tissue is scattered throughout the body with some portions lying well below the skin and not easily found. A technique for tracing the tissues of this system would provide information to immunologists tracing antigen-antibody combinations, and, conceivably, to surgeons performing radical lymph node dissections. The data presented are consistent with the hypothesis that lymph nodetissue specific antibody had been prepared and labeled and that the antibody, when injected, traced the lymphatic flow of the animal.