IMAGING OF LYMPHOID STRUCTURES WITH 111In LABELLED LYMPHOCYTES

Abstract

Injection of radiolabelled autologous or syngeneic lymphocytes could be used for imaging of the lymphoid structures, providing that the labelling does not interfere with the recirculating properties of the small lymphocytes. The purpose of this study was to assess whether 111In-oxine labelled syngeneic lymphocytes are suitable for imaging both the normal lymphoid structures and those with metastatic disease.

51 ACI rats were studied. 31 of the animals were injected in the left foot pad with 1x106 syngeneic H-4-II-E hepatoma cells 9–44 days before imaging. Most of them were bearing palpable tumors when imaged. In all experiments, 2–4 x 108111In-oxine labelled lymphocytes with a specific activity of 35–45 μCi/108 cells were injected intravenously. Gamma camera images were obtained 1–72 hours later. Following the last image the animals were killed. The cervical, iliac, inguinal, and popliteal lymph nodes, liver, spleen, lung and left femur were dissected and the recovered radioactivity was determined in a gamma well counter

In 68% of the animals there was partial or complete visualization of the lymph nodes. Large metastatic nodes were well seen. The 111In labelled lymphocytes exhibited a normal migration pattern; 10–13% were recovered per gram of lymphoid tissue at 24 hours.

111In lymphocytes recirculate normally and are suitable for imaging of normal and metastatic lymph nodes. This method has the additional potential to quantitate lymphocyte traffic.

Supported by American Cancer Society research grant No. POL 118A and NIH GM18674–09.