OCH, an a-galactosylceramide analogue with a truncated side chain, stimulates Th2-biased cytokine production in natural killer T cells. Through a collaboration with Dr. Paul Savage at Brigham Young University, the NIH Tetramer Facility is providing mouse and human CD1d monomers and tetramers loaded with OCH. Purified OCH ligand may also be obtained for stimulation of NK T cells in vitro or for in vivo animal studies. (The material may not be used in humans.) OCH is dissolved in a Tween/sucrose/histidine buffer, sterile-filtered, placed in autoclaved vials, and lyophilized. The resulting powder can be reconstituted in water at a final concentration of 0.2 mg/mL.