Submitted April 6, 2006
Accepted August 15, 2006
Massive infection and loss of CD4+ T cells occurs in the intestinal tract of neonatal rhesus macaques in acute SIV infection
Xiaolei Wang, Terri Rasmussen, Bapi Pahar, Bhawna Poonia, Xavier Alvarez, Jason Dufour, Andrew A. Lackner, and Ronald S. Veazey*
Tulane National Primate Research Center, Tulane University School of Medicine, Covington, LA
* Corresponding author; email: rveazey{at}tulane.edu.
Rapid, profound, and selective depletion of memory CD4+ T cells has now been confirmed to occur in simian immunodeficiency virus (SIV) infected adult macaques and human immunodeficiency virus (HIV) infected humans. Within days of infection, marked depletion of memory CD4+ T cells occurs primarily in mucosal tissues, the major reservoir for memory CD4+ T cells in adults. However, HIV infection in neonates often results in higher viral loads and rapid disease progression, despite the paucity of memory CD4+ T cells in the peripheral blood. Here we examined the immunophenotype of CD4+ T cells in normal and SIV-infected neonatal macaques to determine the distribution of naive and memory T cell subsets in tissues. We demonstrate that, similar to adults, neonates have abundant memory CD4+ T cells in the intestinal tract and spleen, and that these are selectively infected and depleted in primary SIV infection. Within 12 days of SIV infection, activated (CD69+), central memory (CD95+CD28+) CD4+ T cells are marked and persistently depleted in the intestine and other tissues of neonates compared to controls. The results indicate that "activated" central memory CD4+ T cells are the major target for early SIV infection and CD4+ T cell depletion in neonatal macaques.
