[1] St Louis Univ, Sch Med, Edward A Doisy Dept Biochem & Mol Biol, St Louis, MO 63104 USA
[2] St Louis Univ, Sch Med, Dept Pathol, St Louis, MO 63104 USA
[3] St Louis Univ, Sch Med, Dept Microbiol & Immunol, St Louis, MO 63104 USA
[4] Univ Massachusetts, Dept Med, Worcester, MA 01605 USA