[1] Vanderbilt Univ, Sch Med, Dept Pediat, Nashville, TN 37212 USA
[2] Vanderbilt Univ, Sch Med, Dept Pathol Microbiol & Immunol, Nashville, TN 37212 USA
[3] Vanderbilt Univ, Sch Med, Elizabeth B Lamb Ctr Pediat Res, Nashville, TN 37212 USA
[4] Univ Calif Irvine, Dept Microbiol & Mol Genet, Irvine, CA 92717 USA
[5] Princeton Univ, Dept Mol Biol, Princeton, NJ 08544 USA