title: Accumulation of MAC387+ macrophages in paracortical areas of lymph nodes in rhesus monkeys acutely infected with simian immunodeficiency virus.
abstract: We investigated the histological features of lymph nodes, focusing on monocytes/macrophages, in rhesus monkeys (Macaca mulatta) acutely infected with simian immunodeficiency virus (SIV). In monkeys infected with a pathogenic SIV, SIVmac239, MAC387(+) newly blood-derived macrophages markedly increased in number at paracortical areas at 11 to 14 days postinoculation, concomitant with the peak of the primary SIV antigenemia. The MAC387(+) macrophages densely gathered around high endothelial venules and formed cell clusters with CD3(+) T lymphocytes, tingible body macrophages, and plasmacytoid monocytes. In the cell clusters, CD3(+) T lymphocytes which closely adhered to the MAC387(+) macrophages enlarged in size, suggesting a histological manifestation of T-lymphocyte activation by macrophages. By 54 days postinoculation, when SIV antigenemia became undetectable, the MAC387(+) macrophages decreased in number and the cell cluster disappeared from paracortical areas. In contrast, the monkeys infected with a nef-deleted mutant of SIVmac239 showed lower levels of SIV antigenemia and lower numbers of MAC387(+) macrophages in paracortical areas than those infected with SIVmac239. These results indicate that MAC387(+) macrophages accumulate in paracortical areas for the period of the intense primary SIV antigenemia and may play an important role in activating naive T lymphocytes.
authors.affiliation: Tsukuba Primate Center, National Institute of Infectious Diseases, 1 Hachimandai, Tsukuba, Ibaraki 305-0843, Japan.
authors.forename: I
authors.initials: I
authors.lastname: Otani
authors.forename: K
authors.initials: K
authors.lastname: Mori
authors.forename: T
authors.initials: T
authors.lastname: Sata
authors.forename: K
authors.initials: K
authors.lastname: Terao
authors.forename: K
authors.initials: K
authors.lastname: Doi
authors.forename: H
authors.initials: H
authors.lastname: Akari
authors.forename: Y
authors.initials: Y
authors.lastname: Yoshikawa
mesh_terms: D000818:Animals; D000956:Antigens, Viral / Q000097:blood; D002449:Cell Aggregation; D015683:Gene Products, gag / Q000097:blood; D017403:In Situ Hybridization; D007700:Kinetics; D008198:Lymph Nodes / Q000276:immunology / Q000473:pathology*; D008253:Macaca mulatta; D008264:Macrophages / Q000166:cytology / Q000276:immunology; D016097:Simian Acquired Immunodeficiency Syndrome / Q000276:immunology / Q000473:pathology* / Q000821:virology; D015302:Simian Immunodeficiency Virus / Q000302:isolation & purification
chemical_list: D000956:Antigens, Viral; C066594:Gag protein p27, Simian immunodeficiency virus; D015683:Gene Products, gag