[Biodistribution of immune cells in adoptive immunotherapy by using GFP transgenic mice]

All of the cells and tissues from GFP transgenic mice, with the exception of erythrocytes and hair, express green fluorescent protein. Additionally, lymphokine activated killer cells induced from splenocytes of the mice (GFP-LAK) express green fluorescence under the observation by fluorescent microscopy. In the present study, we studied the biodistribution of LAK in the two adoptive immunotherapy models by injecting GFP-LAK into non-GFP expressing syngeneic mice. In peritoneal dissemination model of B16 melanoma cells, intraperitoneally injected GFP-LAK accumulated densely on the tumor. On the other hand, in the lung metastases model, intravenously injected GFP-LAK stayed scattered around the tumor, although they were observed abundantly in the spleen. Our adoptive transfer model using GFP transgenic mice is useful for understanding antitumor mechanisms induced by adoptively transferred immune cells, without any troublesome marking procedures.