title: The microvesicle component of HIV-1 inocula modulates dendritic cell infection and maturation and enhances adhesion to and activation of T lymphocytes.
abstract: HIV-1 is taken up by immature monocyte derived dendritic cells (iMDDCs) into tetraspanin rich caves from which the virus can either be transferred to T lymphocytes or enter into endosomes resulting in degradation. HIV-1 binding and fusion with the DC membrane results in low level de novo infection that can also be transferred to T lymphocytes at a later stage. We have previously reported that HIV-1 can induce partial maturation of iMDDCs at both stages of trafficking. Here we show that CD45⁺ microvesicles (MV) which contaminate purified HIV-1 inocula due to similar size and density, affect DC maturation, de novo HIV-1 infection and transfer to T lymphocytes. Comparing iMDDCs infected with CD45-depleted HIV-1BaL or matched non-depleted preparations, the presence of CD45⁺ MVs was shown to enhance DC maturation and ICAM-1 (CD54) expression, which is involved in DC∶T lymphocyte interactions, while restricting HIV-1 infection of MDDCs. Furthermore, in the DC culture HIV-1 infected (p24⁺) MDDCs were more mature than bystander cells. Depletion of MVs from the HIV-1 inoculum markedly inhibited DC∶T lymphocyte clustering and the induction of alloproliferation as well as limiting HIV-1 transfer from DCs to T lymphocytes. The effects of MV depletion on these functions were reversed by the re-addition of purified MVs from activated but not non-activated SUPT1.CCR5-CL.30 or primary T cells. Analysis of the protein complement of these MVs and of these HIV-1 inocula before and after MV depletion showed that Heat Shock Proteins (HSPs) and nef were the likely DC maturation candidates. Recombinant HSP90α and β and nef all induced DC maturation and ICAM-1 expression, greater when combined. These results suggest that MVs contaminating HIV-1 released from infected T lymphocytes may be biologically important, especially in enhancing T cell activation, during uptake by DCs in vitro and in vivo, particularly as MVs have been detected in the circulation of HIV-1 infected subjects.
authors.affiliation: Centre for Virus Research, Westmead Millennium Institute, Westmead, New South Wales, Australia ; University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Sarah K
authors.initials: SK
authors.lastname: Mercier
authors.forename: Heather
authors.initials: H
authors.lastname: Donaghy
authors.forename: Rachel A
authors.initials: RA
authors.lastname: Botting
authors.forename: Stuart G
authors.initials: SG
authors.lastname: Turville
authors.forename: Andrew N
authors.initials: AN
authors.lastname: Harman
authors.forename: Najla
authors.initials: N
authors.lastname: Nasr
authors.forename: Hong
authors.initials: H
authors.lastname: Ji
authors.forename: Ulrike
authors.initials: U
authors.lastname: Kusebauch
authors.forename: Luis
authors.initials: L
authors.lastname: Mendoza
authors.forename: David
authors.initials: D
authors.lastname: Shteynberg
authors.forename: Kerrie
authors.initials: K
authors.lastname: Sandgren
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Simpson
authors.forename: Robert L
authors.initials: RL
authors.lastname: Moritz
authors.forename: Anthony L
authors.initials: AL
authors.lastname: Cunningham
mesh_terms: D002448:Cell Adhesion / Q000276:immunology; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000276:immunology* / Q000473:pathology / Q000821:virology*; D015658:HIV Infections / Q000276:immunology* / Q000473:pathology; D015497:HIV-1 / Q000276:immunology*; D006801:Humans; D008213:Lymphocyte Activation; D009000:Monocytes / Q000276:immunology / Q000473:pathology; D013601:T-Lymphocytes / Q000276:immunology* / Q000473:pathology