Attempt to augment the anti-proliferative effect of recombinant human lymphotoxin in combined use with anti-tumor antibody-diethyldithiocarbamate conjugates.

We have attempted to augment specifically the antiproliferative effect of recombinant human lymphotoxin (rhLT) on tumor cells in combined use with diethyldithiocarbamate (DDC) which is known to inactivate superoxide dismutase. For this purpose, anti-Meth A tumor cell antibody-DDC conjugates were used to confer the selectivity on the augmented antiproliferative effect in combined use of rhLT with DDC. Simultaneous addition of rhLT (1 u/ml to 100 u/ml) with the diluted conjugates to the target Meth A tumor cells induced the augmentation of the antiproliferative effect although antibody control was not effective. Similar augmentation of the antiproliferative effect was obtained when the target cells were treated with the conjugates prior to the addition of rhLT although the rate of inhibition was low. This approach seems to be useful because the antiproliferative effect of LT on target tumor cells could be augmented and side effects of LT could be avoided.