Purity and transplantation properties of tumor cell suspensions.

Cell debris is inevitably produced by the mechanical and enzymatic procedures used to dissociate solid tumors. We investigated the influence of such debris on the i.v. and s.c. transplantability of B16 melanoma cells. Cell suspensions were centrifuged on a Percoll cushion to remove the debris, and the purified preparations were compared to untreated control suspensions. The i.v. injection of a massive dose (10(6) cells) of unpurified cells killed the animals within a few minutes, while the same amount of purified cells left the animals unaffected. When 5 X 10(5) cells were given, animals receiving purified cell suspensions had more extrapulmonary tumors at their time of death than those given unpurified cells. However, with a lower cell dose, 2 X 10(4) cells, there were no such differences in tumor incidence or distribution.