title: Intestinal double-positive CD4+CD8+ T cells of neonatal rhesus macaques are proliferating, activated memory cells and primary targets for SIVMAC251 infection.
abstract: Peripheral blood and thymic double-positive (DP) CD4(+)CD8(+) T cells from neonates have been described earlier, but the function and immunophenotypic characteristics of other tissue-derived DP T cells are not clearly understood. Here, we demonstrate the functional and immunophenotypic characteristics of DP cells in 6 different tissues, including thymus from normal neonatal rhesus macaques (Macaca mulatta) between 0 and 21 days of age. In general, intestinal DP T cells of neonates have higher percentages of memory markers (CD28(+)CD95(+)CD45RA(low)CD62L(low)) and proliferation compared with single-positive (SP) CD4(+) and CD8(+) T cells. In addition, percentages of DP T cells increase and CD62L expression decreases as animals mature, suggesting that DP cells mature and proliferate with maturity and/or antigen exposure. Consistent with this, intestinal DP T cells in neonates express higher levels of CCR5 and are the primary targets in simian immunodeficiency virus (SIV) infection. Finally, DP T cells produce higher levels of cytokine in response to mitogen stimulation compared with SP CD4(+) or CD8(+) T cells. Collectively, these findings demonstrate that intestinal DP T cells of neonates are proliferating, activated memory cells and are likely involved in regulating immune responses, in contrast to immature DP T cells in the thymus.
authors.affiliation: Divisions of Comparative Pathology, Tulane National Primate Research Center, Tulane University School of Medicine, Covington, LA, USA.
authors.forename: Xiaolei
authors.initials: X
authors.lastname: Wang
authors.forename: Arpita
authors.initials: A
authors.lastname: Das
authors.forename: Andrew A
authors.initials: AA
authors.lastname: Lackner
authors.forename: Ronald S
authors.initials: RS
authors.lastname: Veazey
authors.forename: Bapi
authors.initials: B
authors.lastname: Pahar
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000821:virology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000821:virology; D002454:Cell Differentiation; D049109:Cell Proliferation; D016207:Cytokines / Q000096:biosynthesis; D007156:Immunologic Memory; D007422:Intestines / Q000276:immunology*; D008253:Macaca mulatta; D016097:Simian Acquired Immunodeficiency Syndrome / Q000473:pathology*
chemical_list: D016207:Cytokines