Therapeutic effect of neuraminidase-treated LAK cells on liver metastasis of Colon 26

To improve the lymphokine-activated killer (LAK) cell therapy for liver metastasis, two methods which enhance accumulation of LAK cells in the liver were examined for their effects on the liver metastasis of Colon 26 cancer cells in BALB/c mice. Distribution of LAK cells in the mice was examined by the 51Cr labeling method. Portal vein infusion of LAK cells or tail vein infusion of neuraminidase treated-LAK (N-LAK) cells showed an augmented accumulation of infused cells in the liver. In the first experiment, LAK cells (5 x 10(7) cells) were infused in the portal vein or tail vein at days 3 and 7 after the inoculation of 5 x 10(4) tumor cells and 1 x 10(4) units of IL-2 were given three times a day from day 3 to day 7. The portal infusion of LAK cells produced a greater reduction of liver metastases compared with the peripheral infusion. In the second experiment, 5 x 10(7) LAK cells or N-LAK cells were infused via the tail vein on days 1 and 3, and 1 x 10(4) units of IL-2 were given once a day from day 1 to day 5 after the inoculation of 1 x 10(4) tumor cells. The therapeutic effect of N-LAK cells was greater than non-treated LAK cells on the number of metastatic lesions and the survival time of mice. Since access to the human portal vein is difficult and risky in clinical situation, peripheral infusion of N-LAK cells is preferable.