7DW8-5

EF77 is a plakoside A-like glycolipid, a GSL isolated from the marine sponge, Plakortis simplex, and is related to the previously crystallized SMC124 lipid. The sugar headgroup and O-glycosidic linkage are identical to GalCer, but the acyl chain has been modified to mimic plakoside A, with a cyclopropyl group and double bond between carbons 4 and 5. Like EF77, 7DW8-5 also has a modification in the acyl group. The length of the chain has been shortened to 11 carbons and a parafluor-phenyl group has been added. The rationale behind those different modifications is that changes in the lipid moiety would be expected to mainly influence the lipid interaction with CD1d, whereas changes in the galactose moiety and linkage can affect interaction with CD1d; the TCR and they could confer resistance to endoglycosidases upon injection into mice and thus could increase the half-life in serum.