[1] Schering Plough Corp, Res Inst, Dept Immunol, Kenilworth, NJ 07033 USA
[2] Schering Plough Corp, Res Inst, Dept Drug Safety & Metab, Kenilworth, NJ 07033 USA
[3] DNAX Res Inst Mol & Cellular Biol Inc, Dept Immunol, Palo Alto, CA 94304 USA
[4] Univ Michigan, Sch Med, Dept Pathol, Ann Arbor, MI 48109 USA