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Background. Although virus-specific CD4+ T lymphocytes emerge rapidly during primary cytomegalovirus (CMV) infection in humans, they exhibit a state of prolonged functional exhaustion of unknown etiology. To investigate the suitability of rhesus macaques as a model of primary human CMV infection, we examined the virologic and immunologic features of naturally acquired primary CMV infection in rhesus macaques.Methods. CMV-specific CD4+ T lymphocytes and CMV load in blood, saliva, and urine were evaluated in a cohort of simian immunodeficiency virus (SIV)–negative rhesus macaques stratified by age into infant, juvenile, and adult groups.Results. CMV infection was detected in juvenile and adult monkeys but not in infant monkeys. CMV loads and shedding frequency in urine and saliva were significantly higher in the 2–3-year old juvenile monkeys, compared with the adult monkeys. The increased CMV load in juvenile monkeys was associated with lower polyfunctionality, impaired proliferation, and increased expression of the inhibitory receptor PD-1 in CMV-specific CD4+ T lymphocytes. The proliferative defect was partially reversible by exogenous PD-1 blockade or addition of interleukin 2.Conclusions. Postnatal acquisition of primary CMV infection in rhesus macaques results in prolonged virus excretion and impaired CMV-specific CD4+ T-lymphocyte function, findings that recapitulate key features of primary CMV infection in humans. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Enterocytozoon bieneusi is closely linked with chronic diarrhea and wasting in AIDS. Although reported > 10 years ago, little is known about the infection and the disease it induces in humans. Duodenal E. bieneusi spores froman AIDS patient were orally transmitted to 2 simian immunodeficiency virus-infected rhesus monkeys. Both animals began shedding spores within a week of inoculation, as confirmed by microscopy and polymerase chain reaction, and continued until euthanatized 7 and 8 months later. E. bieneusi infection in the gut was sparse, either because of moderate numbers of circulating CD4 cells or because monkeys are less susceptible than humans to this infection. This is apparently the first documented transmission of E. bieneusi infection between hosts. [ABSTRACT FROM PUBLISHER]