Immunochemical studies of organ and tumor lipids XXI. Sensitivity and specificity of the cytolipin F - sheep erythrocyte system.

The sensitivity and specificity of the sheep erythrocyte - anti-sheep erythrocyte system to inhibition by pure cytolipin F has been studied with 5 antisera, in order to compare it with the rat erythrocyte-anti-rat lymphosarcoma system and its inhibition by pure cytolipin R. The cytolipin F - sheep erythrocyte system is much more sensitive than the cytolipin R - rat erythrocyte system, inhibition of hemolysis of 6 x 10(6) sheep cells being produced by 10 ng of cytolipin F (combined with a four-fold quantity of lecithin) compared with inhibition of hemolysis of 10(6) rat cells by 50 to 100 ng of cytolipin R (also combined with lecithin). Differences in sensitivity are attributed to the larger number of available cytolipin F determinants on sheep erythrocytes compared with cytolipin R determinants on rat erythrocytes. Studies of the auxiliary lipid enhancement of cytolipin F activity by galactocerebroside, lactosyl ceramide (cytolipin H), and lecithin are also reported.