[In vivo distributions of 111In and/or 3H labeled lymphocyte in C3H/He mouse (author's transl)].

: Although 99mTc and 51Cr have been used for lymphocyte labeling, these radionuclides have several disadvantages for study on immunological behaviour of lymphocyte; very high rate elution and low labeling efficiency for both radionuclides, and short half life for 99mTc. Indium-111 has quite suitable physical properties for clinical nuclear medicine, i.e. desirable photon energy (247,173 keV) and 2.8 day half life. 111In-oxine is lipid soluble and is known to pass through the cell membrane and attaches firmly to cytoplasmic component of the cell. On the other hand, 3H-thymidine is well known substance which incorporated to nucleic acid in the cell. In this study, distribution patterns of 111In-oxine and/or 3H-thymidine labeled lymphocyte in C3H/He mice were examined and the suitability of 111In-oxine labeled lymphocyte for radionuclide imaging in vivo was discussed. Thirty minutes after intravenous injection of 3H and/or 111In labeled lymphocyte, about 12% of lymphocyte were found in the lungs and rest of them were distributed mainly in the blood, kidneys and liver. After 24 hours the activity in the lung decreased markedly and the activity in the liver and kidneys increased with time. Between lymphocyte labeled with 111In-oxine and 3H-thymidine, there is not so much differences in terms of distribution patterns. From this study, it is concluded that the 111In-oxine labeled lymphocyte distributes in the same way as 3H labeled one, in spite of different labeling sites. This 111In-oxine labeling method can be used as a useful tool of radionuclide imaging in kinetic studies of lymphocyte in vivo.