[1] Univ N Carolina, Dept Microbiol & Immunol, Chapel Hill, NC 27599 USA
[2] Univ N Carolina, Carolina Vaccine Inst, Chapel Hill, NC 27599 USA
[3] Duke Univ, Med Ctr, Dept Pathol, Durham, NC 27710 USA
[4] Duke Univ, Med Ctr, Dept Pathol, Durham, NC 27710 USA
[5] Duke Univ, Med Ctr, Human Vaccine Inst, Durham, NC 27710 USA