title: Simian immunodeficiency virus infection in neonatal macaques.
abstract: Children with human immunodeficiency virus infection often have higher viral loads and progress to AIDS more rapidly than adults. Since the intestinal tract is a major site of early viral replication and CD4(+) T-cell depletion in adults, we examined the effects of simian immunodeficiency virus (SIV) on both peripheral and intestinal lymphocytes from 13 neonatal macaques infected with SIVmac239. Normal neonates had more CD4(+) T cells and fewer CD8(+) T cells in all tissues than adults. Surprisingly, neonates had substantial percentages of CD4(+) T cells with an activated, memory phenotype (effector CD4(+) T cells) in the lamina propria of the intestine compared to peripheral lymphoid tissues, even when examined on the day of birth. Moreover, profound and selective depletion of jejunum lamina propria CD4(+) T cells occurred in neonatal macaques within 21 days of infection, which was preceded by large numbers of SIV-infected cells in this compartment. Furthermore, neonates with less CD4(+) T-cell depletion in tissues tended to have higher viral loads. The persistence of intestinal lamina propria CD4(+) T cells in some neonates with high viral loads suggests that increased turnover and/or resistance to CD4(+) T-cell loss may contribute to the higher viral loads and increased severity of disease in neonatal hosts.
authors.affiliation: Tulane National Primate Research Center, Tulane University Health Sciences Center, Covington, Louisiana 70433, USA. veazey@tpc.tulane.edu
authors.forename: Ronald S
authors.initials: RS
authors.lastname: Veazey
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Lifson
authors.forename: Ivona
authors.initials: I
authors.lastname: Pandrea
authors.forename: Jeannette
authors.initials: J
authors.lastname: Purcell
authors.forename: Michael
authors.initials: M
authors.lastname: Piatak
authors.forename: Andrew A
authors.initials: AA
authors.lastname: Lackner
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D006684:HLA-DR Antigens / Q000276:immunology; D017403:In Situ Hybridization; D007583:Jejunum / Q000276:immunology; D008251:Macaca; D012367:RNA, Viral / Q000097:blood; D016097:Simian Acquired Immunodeficiency Syndrome / Q000276:immunology*; D015302:Simian Immunodeficiency Virus / Q000235:genetics / Q000302:isolation & purification; D019562:Viral Load
chemical_list: D006684:HLA-DR Antigens; D012367:RNA, Viral