Direct Evidence of Heterolysis of Gorgonian Target Cells

Abstract

The level of the lysis of a gorgonian target explant following a contact with a xenogeneic or with an allogeneic killer expiant is directly related with the time during which this contact is maintained. This level is also dependent on the mass ratio between the killer explant and the target explant; but only to a certain extent. When, in order to emphasize this mass effect, a target is sandwiched between two killer explants during three hours or more, the resulting lysis is, surprisingly, quite low (only 16% of the target volume lyse under sandwich conditions vs 85% in usual superimposition — target on killer-conditions). The hypothesis was put forward that the observed lytic process required the intervention of cells in normal physiological condition. By means of some system implicating a synthesis in the target explant, surviving cells destroy the cells that have been hit by a toxic (killer) factor. It was also demonstrated by a 14C valine incorporation test that one or two minutes of xenogeneic contact between killer and target explants were sufficient to inflict a measurable damage to target cells (1). The following experiments bring direct evidence adding support to the hypothesis that the lysis of the target cells is a consequence not of the autolysis of these cells, but of their heterolysis by other cells in the target explant (strictly speaking there is autolysis of the target explant, but heterolysis of the target cells). This phenomenon could not appear when all or most of the target cells were dead; as in the sandwich conditions.