[1] Scripps Res Inst, Dept Immunol, La Jolla, CA 92037 USA
[2] Scripps Res Inst, Dept Mol & Expt Med, La Jolla, CA 92037 USA
[3] Vrije Univ Amsterdam Med Ctr, Dept Mol Cell Biol & Immunol, NL-1081 BT Amsterdam, Netherlands
[4] BIOQUAL Inc, Rockville, MD 20850 USA