[1] Univ Iowa, Dept Internal Med, Roy J & Lucille A Carver Coll Med, Iowa City, IA 52242 USA
[2] Univ Iowa, Dept Microbiol, Roy J & Lucille A Carver Coll Med, Iowa City, IA 52242 USA
[3] Univ Iowa, Roy J & Lucille A Carver Coll Med, Dept Mol Physiol & Biophys, Iowa City, IA 52242 USA
[4] Univ Iowa, Dept Biomed Engn, Iowa City, IA 52242 USA
[5] Univ Iowa, Howard Hughes Med Inst, Iowa City, IA 52242 USA