The Journal of Immunology, Vol 125, Issue 3 1196-1200, Copyright © 1980 by American Association of Immunologists

ARTICLES

Modulation of tumor cell susceptibility to humoral immune killing through chemical and physical manipulation of cellular lipid and fatty acid composition

SI Schlager and SH Ohanian

Line-10 tumor cells cultured for 24 hr in lecithin-rich normal human plasma or with synthetic lecithin showed a 5- to 8-fold increase in their lecithin:sphingomyelin mole ratio without being affected in their total lipid content or cholesterol:phospholipid mole ratio. These cells were more sensitive to killing by antibody plus complement (C) than untreated controls. Line-10 cells that underwent a homogeneously catalyzed hydrogenation reaction were reduced 6-fold in their content of unsaturated fatty acid compared to controls; the lipid content of these cells was largely unaffected. These cells were more resistant to antibody-C mediated killing than controls. These modifications in cellular lipid and fatty acid composition could be reversed when the cells were recultured for 24 hr in serum-containing tissue culture medium; the cells regained control levels of susceptibility to antibody- C killing at this time. These results suggest that by manipulating the lipid or fatty acid composition of a tumor cell, either indirectly by changing the lipid composition of the environment in which the cell resides or by directly altering the chemical nature of a cellular lipid constituent, the susceptibility of the cell to humoral immune killing can be modulated.