EFFECTS OF LIPID SUPPLEMENTATION OF CULTURE MEDIA ON CELL-GROWTH, ANTIBODY-PRODUCTION, MEMBRANE-STRUCTURE AND DYNAMICS IN 2 HYBRIDOMAS

Membrane lipid organization and membrane fluidity affect cell function s. The effects of supplementing culture media with a lipid mixture (Ex -Cyte(R)) containing cholesterol, phospholipids and fatty acids on cel l growth, antibody production and membrane composition and dynamics in two hybridoma cell lines were studied. A49 cells decreased immunoglob ulin production but cell growth increased. Lipids had no effect on the cell growth rate of B9 cells but increased immunoglobulin production and productivity. The fluidity of the deep areas of the plasma membran e and cytoplasmic organelles increased in the two cell lines. There wa s increased fluidity of the polar regions of the plasma membrane and a decreased phosphatidylethanolamine/phosphatidylcholine ratio in A49 c ells. B9 cells underwent no change in fluidity of the polar regions bu t the phosphatidylinositol content was increased, together with higher monoclonal antibody production. These results demonstrate that antibo dy production is not linked to the dynamic properties of the membrane, even though changes in the membrane phosphatidylinositol content are associated with the final step of antibody secretion, but that the act ion of phospholipids and fatty acids on cell growth is membrane-associ ated.