Distinct Chemokine Triggers and In Vivo Migratory Paths of Fluorescein Dye-Labeled T Lymphocytes in Acutely Simian Immunodeficiency Virus SIV _mac251 -Infected and Uninfected Macaques

Abstract

To define the possible impact of T-lymphocyte trafficking parameters on simian immunodeficiency virus (SIV) pathogenesis, we examined migratory profiles of carboxyfluorescein diacetate succinimidyl ester (CFSE)-labeled T lymphocytes in acutely SIV mac251 -infected and uninfected macaques within 48 h after autologous transfer. Despite significant upregulation of homeostatic chemokine CCL19/macrophage inflammatory protein 3␤ and proinflammatory chemokine CXCL9/monokine induced by gamma interferon in secondary lymphoid tissue in SIV infection, no differences in CFSE ؉ T-lymphocyte frequencies or cell compartmentalization in lymph nodes were identified between animal groups. By contrast, a higher frequency of CFSE ؉ T lymphocytes in the small intestine was detected in acute SIV infection. This result correlated with increased numbers of gut CD4 T lymphocytes expressing chemokine receptors CCR9, CCR7, and CXCR3 and high levels of their respective chemokine ligands in the small intestine. The changes in trafficking parameters in SIV-infected macaques occurred concomitantly with acute gut CD4 T-lymphocyte depletion. Here, we present the first in vivo T-lymphocyte trafficking study in SIV infection and a novel approach to delineate T-lymphocyte recruitment into tissues in the nonhuman primate animal model for AIDS. Such studies are likely to provide unique insights into T-lymphocyte sequestration in distinct tissue compartments and possible mechanisms of CD4 T-lymphocyte depletion and immune dysfunction in simian AIDS.

Decreased CXCR3+CD8 T Cells in Advanced Human Immunodeficiency Virus Infection Suggest that a Homing Defect Contributes to Cytotoxic T-Lymphocyte Dysfunction

“…Another study described an increase in CXCR3 ϩ CD8 T cells in the lungs of HIV-infected subjects with alveolitis (1). Furthermore, in acutely SIV-infected macaques, CXCR3 was important for trafficking both to lymph nodes and the small intestine (11). Our current studies demonstrate that CXCR3 is also uniquely important for the homing of CTL to infected lymphoid tissue in HIV infection.…”

Neuroinvasion of Fluorescein-Positive Monocytes in Acute Simian Immunodeficiency Virus Infection

“…Viral RNA levels in plasma and CSF were determined by SIV real-time TaqMan PCR analysis based on amplification of a SIV gag gene-containing plasmid with established primer and probe pairs, as previously described (12,34). Data are presented as viral RNA copies per milliliter of CSF or EDTA plasma.…”

“…Complete blood cell counts were monitored throughout the acute infection phase. The sequential phlebotomy procedure was conducted for isolation of a large number of PBMC as previously described (11,12). In brief, on day zero for uninfected macaques or on day 12 postinfection (p.i.)…”

“…In brief, on day zero for uninfected macaques or on day 12 postinfection (p.i.) for SIV-infected macaques, animals were sequentially bled and PBMC were isolated and dye labeled with 5 M carboxyfluorescein diacetate, succinimidyl ester (CFSE) prior to autologous transfer of CFSE dye-labeled cells via the intravenous route (11,12). The numbers of transferred CFSE dye-labeled monocytes in both animal groups (three SIV-infected and four uninfected macaques) ranged from 0.8 ϫ 10 7 to 10 ϫ 10 7 cells based on transfer of 2.1 ϫ10 8 to 7.4 ϫ10 8 total PBMC.…”

“…CXCL9 transcript levels of brain tissue were assessed using the comparative cycle threshold (C T ) method (User Bulletin 2; Applied Biosystems) on a 7900 HTA FAST SDS real-time platform (Applied Biosystems, Foster City, CA) with previously established probes and procedures (11,12). In brief, a coisolation procedure was used to extract total RNA and genomic DNA from 30-m-thick paraffin-embedded cerebral tissue sections using the DNeasy tissue kit (QIAGEN, Valencia, CA).…”