Alterations of characteristic temperatures for lectin interactions in LM cells with altered lipid composition

Alteration of the fatty acid composition of mouse LM cell lipids dramatically affected the concanavalin A binding and concanavalin A-mediated hemadsorption properties of these cells. A critical temperature for these two concanavalin A related phenomena observed at 15–19° in cells with unaltered fatty acid composition was shifted to 22–28° for cells containing a higher proportion of saturated fatty acids and lowered to 7–11° for cells containing polyunsaturated fatty acids substituted for monoenoic unsaturated fatty acids. In contrast, a second critical temperature (at 5–7°) observed for concanavalin A binding and concanavalin A-mediated hemadsorption to LM cells was essentially unchanged by alterations in cellular lipid fatty acid composition. We conclude that a change in membrane lipid freezing point is responsible for the higher critical temperature (15–19°), and factors other than lipid melting properties, perhaps cytoskeleton structure, contribute to the lower critical temperature (5–7°) for lectin interactions with the exposed surface of LM cells.