Stimulation of Synthesis and Release of Lipids in Tumor Cells Under Attack by Antibody Plus Complement

Resistance to antibody-complement- (Ab-C) mediated killing of guinea pig hepatoma cells (line-1 and line-10) correlates with the ability of the cells to synthesize lipids, but not DNA, RNA, protein, or complex carbohydrate. We therefore studied the synthesis and release of macromolecules (especially lipids) by tumor cells under attack by Ab plus C.

Ab-sensitized tumor cells (TA) incorporated increased amounts of acetate, glycerol, or fatty acids into complex lipids compared to control cells within 5 to 10 min after the addition of guinea pig C (GPC) to the cells (TAC). TA, TC, or TAΔC (Ab plus heat-inactivated GPC) did not show this effect. No enhancement of DNA, RNA, or protein synthesis in TAC as compared with control cells was noted. Line-1 cells, which are killed by GPC when sensitized with excess anti-Forssman Ab (TA_xs), demonstrated enhanced lipid synthesis within 1 to 3 min after the addition of GPC to TA_xs, before measurable killing of the cells had occurred.