title: A cryptic sensor for HIV-1 activates antiviral innate immunity in dendritic cells.
abstract: Dendritic cells serve a key function in host defence, linking innate detection of microbes to activation of pathogen-specific adaptive immune responses. Whether there is cell-intrinsic recognition of human immunodeficiency virus (HIV) by host innate pattern-recognition receptors and subsequent coupling to antiviral T-cell responses is not yet known. Dendritic cells are largely resistant to infection with HIV-1, but facilitate infection of co-cultured T-helper cells through a process of trans-enhancement. Here we show that, when dendritic cell resistance to infection is circumvented, HIV-1 induces dendritic cell maturation, an antiviral type I interferon response and activation of T cells. This innate response is dependent on the interaction of newly synthesized HIV-1 capsid with cellular cyclophilin A (CYPA) and the subsequent activation of the transcription factor IRF3. Because the peptidylprolyl isomerase CYPA also interacts with HIV-1 capsid to promote infectivity, our results indicate that capsid conformation has evolved under opposing selective pressures for infectivity versus furtiveness. Thus, a cell-intrinsic sensor for HIV-1 exists in dendritic cells and mediates an antiviral immune response, but it is not typically engaged owing to the absence of dendritic cell infection. The virulence of HIV-1 may be related to evasion of this response, the manipulation of which may be necessary to generate an effective HIV-1 vaccine.
authors.affiliation: Molecular Pathogenesis Program, The Kimmel Center for Biology and Medicine of the Skirball Institute, New York University School of Medicine, New York, New York 10016, USA.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Manel
authors.forename: Brandon
authors.initials: B
authors.lastname: Hogstad
authors.forename: Yaming
authors.initials: Y
authors.lastname: Wang
authors.forename: David E
authors.initials: DE
authors.lastname: Levy
authors.forename: Derya
authors.initials: D
authors.lastname: Unutmaz
authors.forename: Dan R
authors.initials: DR
authors.lastname: Littman
mesh_terms: D036022:Capsid Proteins / Q000276:immunology; D002460:Cell Line; D021984:Cyclophilin A / Q000276:immunology; D003713:Dendritic Cells / Q000166:cytology / Q000276:immunology* / Q000378:metabolism / Q000821:virology*; D015658:HIV Infections / Q000276:immunology* / Q000821:virology; D015497:HIV-1 / Q000276:immunology* / Q000502:physiology; D006801:Humans; D007113:Immunity, Innate; D050838:Interferon Regulatory Factor-3 / Q000235:genetics / Q000378:metabolism; D008213:Lymphocyte Activation; D009000:Monocytes / Q000166:cytology; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D036022:Capsid Proteins; D050838:Interferon Regulatory Factor-3; D021984:Cyclophilin A