Accumulation of MAC387+ macrophages in paracortical areas of lymph nodes in rhesus monkeys acutely infected with simian immunodeficiency virus

nef Gene Is Required for Robust Productive Infection by Simian Immunodeficiency Virus of T-Cell-Rich Paracortex in Lymph Nodes

“…For in situ hybridization, we used riboprobes that were complementary to SIV gag, pol, and nef regions and were labeled by incorporation of digoxigenin-UTP (Roche Diagnostics). SIV RNA was detected in tissue sections by in situ hybridization as previously described (36,39). Briefly, dewaxed sections were pretreated with 0.2 N hydrochloric acid for 20 min, digested with 20 g of proteinase K/ml at 37°C for 15 min, and acetylated.…”

“…The importance of early events in AIDS virus infection in terms of viral replication, host immune response, and disease progression has been reported from HIV type 1 (HIV-1) clinical studies (45) and studies of animal AIDS models (34). In particular, due to considerations of feasibility in study design, early events of SIV infection in macaques were extensively investigated by examination of various tissues, viral strains, and infection routes (9,10,23,29,39,44,50,51,(54)(55)(56)(57). Reimann et al, using SIVmac251, reported that SIV-infected cells localized predominantly in T-cell-rich extrafollicular regions in lymph nodes (LNs) at primary infection (44).…”

Splenic Damage during SIV Infection

“…In agreement with our finding of a temporal restriction of Mac387 cells, newly disseminated Mac387 macrophages were shown to occur transiently in the lymph nodes of SIV-infected macaques. 82 This suggests that Mac387 macrophages enter into tissues after high levels of viremia, and may be an indicator of early SIV/HIV-mediated damage. Newly infiltrated splenic Mac387 macrophages may be deleterious, as they promote lymphoid destruction, viremia, and pathology.…”

“…Newly infiltrated splenic Mac387 macrophages may be deleterious, as they promote lymphoid destruction, viremia, and pathology. 82,83 Alternatively, the recruitment of these cells may represent a protective response, in an attempt to mitigate the loss of and changes to CD68 and CD163 macrophage populations during SIV infection.…”

Distinct temporal programming of naive CD4+ T cells for cell division versus TCR‐dependent death susceptibility by antigen‐presenting macrophages

“…Although they are less potent stimulators than dendritic cells, macrophages are involved in the initiation of T cell immune responses against simian immunodeficiency virus [22], Borrelia burgdorferi [23,24], corneal allografts [25], and DNA vaccines [26,27]. We observed a clear synchrony in T cell commitment to surface TCR up-regulation [28], minimal T cell division, and the development of TCRdependent death susceptibility in vitro.…”