Figure 4.

GPI-associated diacylglycerol is required for maximal downstream gene expression. (A) Reverse transcription–PCR confirms that GPIs induce de novo expression of TNF-α and IL-1α in macrophages. (B) de novo TNF expression is reduced in response to inositolglycan, indicating that the GPI-associated fatty acids are required for maximal downstream gene expression. (C) Induction of TNF output by GPI precursors. Macrophages were pulsed with 1 μM glycolipids Pfglα, β, γ, δ, and ɛ for 2 h and the level of TNF determined by capture ELISA. The other glycolipid peaks (ζ, ν, and θ; data not shown) and sham-treated TLC plates had no effect. (D) Inositolglycan (10 μm) and lyso-GPI are unable to induce TNF output. (E) iM4 GIPL, PI, and lyso-PI (10 μm) are unable to induce TNF output. (F) iM4 inhibits LPS-induced TNF output in RAW 264 cells.