C2 L-threo Ceramide is a bioactive sphingolipid and cell-permeable analog of naturally occurring ceramides. It stimulates cholesterol efflux in CHO cells expressing the human ABCA1 receptor when used at a concentration of 10 μM, however, this efflux is 50% less than that stimulated by C2 ceramide . C2 L-threo Ceramide inhibits IL-4 production by 17% in EL4 T cells stimulated with phorbol 12-myristate 13-acetate when used at a concentration of 10 μM. It also induces cell cycle arrest in the G0/G1 phase and a 7-fold increase in sphingosine accumulation as well as inhibits growth of HL-60 leukemia cells.