Preservation of memory CD4+ T lymphocytes in breast milk of lactating rhesus monkeys during acute simian immunodeficiency virus infection

Abstract

Acute human immunodeficiency virus (HIV) or simian immunodeficiency virus (SIV) infection is associated with a massive depletion of memory CD4+ T lymphocytes in the gastrointestinal tract. To define the dynamics of the CD4+ T lymphocyte subpopulations in breast milk during acute HIV or SIV infection, lymphocyte populations were monitored in blood and milk of 4 Mamu-A*01+ rhesus monkeys after SIVmac251 inoculation. Strikingly, although the CD4+ T lymphocytes in blood were depleted during the peak of viremia, the milk CD4+ T lymphocyte counts remained unchanged, despite active virus replication in the breast milk compartment. Moreover, CD4+ memory T lymphocytes were preserved in breast milk during acute infection. CD4+ T lymphocytes in breast milk and other mucosal compartments of uninfected monkeys were similar in their memory phenotype, activation status, and chemokine (C-C motif) receptor 5 expression. Interestingly, the number and proportion of effector CD8+ T lymphocytes in milk were increased during acute SIV infection, suggesting effective control of virus-mediated CD4+ T lymphocyte destruction in the breast milk compartment © 2009 by the Infectious Diseases Society of America. All rights reserved.