[1] Louis Stokes Cleveland Dept Vet Affairs Med Ctr, Res Serv, Cleveland, OH 44106 USA
[2] JCVI, Rockville, MD 20850 USA
[3] Univ Michigan, Dept Pediat & Communicable Dis, Med Sch, Ann Arbor, MI 48103 USA
[4] Case Western Reserve Univ, Dept Med, Sch Med, Cleveland, OH 44106 USA
[5] Case Western Reserve Univ, Dept Biochem, Sch Med, Cleveland, OH 44106 USA