title: CTL fail to accumulate at sites of HIV-1 replication in lymphoid tissue.
abstract: The inability of HIV-1-specific CTL to fully suppress virus replication as well as the failure of administration of exogenous CTL to lower viral loads are not understood. To evaluate the hypothesis that these phenomena are due to a failure of CTL to localize at sites of HIV-1 replication, we assessed the distribution of HIV-1 RNA and HIV-1-specific CTL identified by HIV-1 peptide/HLA class I tetrameric complexes (tetramers) within lymph nodes of 14 HIV-1-infected individuals who were not receiving antiretroviral therapy. A median of 0.04% of follicular compared with 0.001% of extrafollicular CD4(+) cells were estimated to be producing HIV-1 RNA, a 40-fold difference (p = 0.0001). Tetramer-stained cells were detected by flow cytometry in disaggregated lymph node cells from 11 subjects and constituted a significantly higher fraction of CD8(+) cells in lymph node (mean, 2.15%) than in PBMC (mean, 1.52%; p = 0.02). In situ tetramer staining in three subjects' lymph nodes, in which high frequencies of tetramer-stained cells were detected, revealed that tetramer-stained cells were primarily concentrated in extrafollicular regions of lymph node and were largely absent within lymphoid follicles. These data confirm that HIV-1-specific CTL are abundant within lymphoid tissues, but fail to accumulate within lymphoid follicles where HIV-1 replication is concentrated, suggesting that lymphoid follicles may be immune-privileged sites. Mechanisms underlying the exclusion of CTL from lymphoid follicles as well as the role of lymphoid follicles in perpetuating other chronic pathogens merit further investigation.
authors.affiliation: Division of Infectious Diseases, University of Colorado at Denver and Health Sciences Center, Denver, CO 80262, USA. liz.connick@uchsc.edu
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Connick
authors.forename: Teresa
authors.initials: T
authors.lastname: Mattila
authors.forename: Joy M
authors.initials: JM
authors.lastname: Folkvord
authors.forename: Rick
authors.initials: R
authors.lastname: Schlichtemeier
authors.forename: Amie L
authors.initials: AL
authors.lastname: Meditz
authors.forename: M Graham
authors.initials: MG
authors.lastname: Ray
authors.forename: Martin D
authors.initials: MD
authors.lastname: McCarter
authors.forename: Samantha
authors.initials: S
authors.lastname: Mawhinney
authors.forename: Aaron
authors.initials: A
authors.lastname: Hage
authors.forename: Cara
authors.initials: C
authors.lastname: White
authors.forename: Pamela J
authors.initials: PJ
authors.lastname: Skinner
mesh_terms: D000328:Adult; D002465:Cell Movement / Q000276:immunology*; D003602:Cytotoxicity, Immunologic; D018984:Epitopes, T-Lymphocyte / Q000276:immunology; D005260:Female; D015497:HIV-1 / Q000276:immunology*; D006801:Humans; D008198:Lymph Nodes / Q000378:metabolism / Q000473:pathology / Q000821:virology; D018655:Lymphocyte Count; D008221:Lymphoid Tissue / Q000276:immunology* / Q000473:pathology / Q000821:virology*; D008297:Male; D008875:Middle Aged; D012367:RNA, Viral / Q000096:biosynthesis; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology* / Q000473:pathology* / Q000821:virology; D014779:Virus Replication / Q000276:immunology*
chemical_list: D018984:Epitopes, T-Lymphocyte; D012367:RNA, Viral