title: Contrasting roles for TLR ligands in HIV-1 pathogenesis.
abstract: The first line of a host's response to various pathogens is triggered by their engagement of cellular pattern recognition receptors (PRRs). Binding of microbial ligands to these receptors leads to the induction of a variety of cellular factors that alter intracellular and extracellular environment and interfere directly or indirectly with the life cycle of the triggering pathogen. Such changes may also affect any coinfecting microbe. Using ligands to Toll-like receptors (TLRs) 5 and 9, we examined their effect on human immunodeficiency virus (HIV)-1 replication in lymphoid tissue ex vivo. We found marked differences in the outcomes of such treatment. While flagellin (TLR5 agonist) treatment enhanced replication of CC chemokine receptor 5 (CCR 5)-tropic and CXC chemokine receptor 4 (CXCR4)-tropic HIV-1, treatment with oligodeoxynucleotide (ODN) M362 (TLR9 agonist) suppressed both viral variants. The differential effects of these TLR ligands on HIV-1 replication correlated with changes in production of CC chemokines CCL3, CCL4, CCL5, and of CXC chemokines CXCL10, and CXCL12 in the ligand-treated HIV-1-infected tissues. The nature and/or magnitude of these changes were dependent on the ligand as well as on the HIV-1 viral strain. Moreover, the tested ligands differed in their ability to induce cellular activation as evaluated by the expression of the cluster of differentiation markers (CD) 25, CD38, CD39, CD69, CD154, and human leukocyte antigen D related (HLA)-DR as well as of a cell proliferation marker, Ki67, and of CCR5. No significant effect of the ligand treatment was observed on apoptosis and cell death/loss in the treated lymphoid tissue ex vivo. Our results suggest that binding of microbial ligands to TLRs is one of the mechanisms that mediate interactions between coinfected microbes and HIV-1 in human tissues. Thus, the engagement of appropriate TLRs by microbial molecules or their mimetic might become a new strategy for HIV therapy or prevention.
authors.affiliation: Section of Intercellular Interactions, Program in Physical Biology, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA. bricbeda@mail.nih.gov
authors.forename: Beda
authors.initials: B
authors.lastname: Brichacek
authors.forename: Christophe
authors.initials: C
authors.lastname: Vanpouille
authors.forename: Yana
authors.initials: Y
authors.lastname: Kiselyeva
authors.forename: Angelique
authors.initials: A
authors.lastname: Biancotto
authors.forename: Melanie
authors.initials: M
authors.lastname: Merbah
authors.forename: Ivan
authors.initials: I
authors.lastname: Hirsch
authors.forename: Andrea
authors.initials: A
authors.lastname: Lisco
authors.forename: Jean Charles
authors.initials: JC
authors.lastname: Grivel
authors.forename: Leonid
authors.initials: L
authors.lastname: Margolis
mesh_terms: D019380:Anti-HIV Agents / Q000276:immunology / Q000494:pharmacology; D018925:Chemokines / Q000276:immunology; D005408:Flagellin / Q000276:immunology / Q000494:pharmacology*; D015658:HIV Infections / Q000188:drug therapy / Q000276:immunology* / Q000821:virology*; D015497:HIV-1 / Q000187:drug effects / Q000276:immunology* / Q000472:pathogenicity / Q000502:physiology; D006801:Humans; D066298:In Vitro Techniques; D008024:Ligands; D009838:Oligodeoxyribonucleotides / Q000276:immunology / Q000494:pharmacology*; D014066:Palatine Tonsil / Q000187:drug effects / Q000276:immunology / Q000821:virology; D051193:Toll-Like Receptors / Q000819:agonists* / Q000276:immunology; D014779:Virus Replication / Q000187:drug effects
chemical_list: D019380:Anti-HIV Agents; D018925:Chemokines; D008024:Ligands; D009838:Oligodeoxyribonucleotides; D051193:Toll-Like Receptors; D005408:Flagellin