IMMUNOBIOLOGY Simian immunodeficiency virus (SIV)–specific cytotoxic T lymphocytes in gastrointestinal tissues of chronically SIV-infected rhesus monkeys

Although systemic virus-specific cyto-toxic T lymphocyte (CTL) responses are of critical importance in controlling virus replication in individuals infected with human immunodeficiency virus 1 (HIV-1), little is known about this immune re-sponse in the gastrointestinal (GI) tract. This study investigated the GI tract CTL response in a nonhuman primate model for HIV-1 infection, simian immunodefi-ciency virus (SIV)–infected rhesus mon-keys. Lymphocytes from duodenal pinch biopsy specimens were obtained from 9 chronically SIVmac-infected rhesus mon-keys and GI tract lymphocytes were har-vested from the jejunum and ileum of 4 euthanized SIVmac-infected rhesus mon-keys. Lymphocytes were also assessed in GI mucosal tissues by in situ staining in histologic specimens. SIVmac Gag-specific CTLs were assessed in the mon-keys using the tetramer technology. These GI mucosal tissues of chronically SIVmac-infected rhesus monkeys contained lev-els of CTLs comparable to those found in the peripheral blood and lymph nodes. The present studies suggest that the CD81 CTL response in GI mucosal sites is com-parable to that seen systemically in SIV-mac-infected rhesus monkeys. (Blood