[1] Louisiana State Univ, Hlth Sci Ctr, Dept Genet, New Orleans, LA 70112 USA
[2] Childrens Hosp Pittsburgh, Pittsburgh, PA 15213 USA
[3] Dartmouth Med Sch, Dept Med & Microbiol & Immunol, Lebanon, NH 03756 USA
[4] Univ Pittsburgh, Sch Med, Ctr Vaccine Res, Pittsburgh, PA 15261 USA
[5] Univ Calif San Diego, Dept Med, La Jolla, CA 92093 USA