Effects of tumor cell culture supernatants on macrophages.

It is proved that supernatants of various tumor cell cultures, as well as cell-free ascitic fluid and sera from tumor bearing animals induce the detachment of macrophages from glass, the loss of their ability to form pseudopodia, the inhibition of their migration and the permeability alteration of their membranes. The cytotoxic effect is not produced by normal tissues, excepting placenta. The effect of tumor cell culture supernatants depends on the characteristic evolution time of each tumor; irradiation diminishes this effect. The involvement of macrophages in immune surveillance and response makes the results interesting for the tumor-host immune relation.