title: Preferential targeting of CD4-CCR5 complexes with bifunctional inhibitors: a novel approach to block HIV-1 infection.
abstract: Two receptors, CD4 and one of several chemokine receptors, are required for cellular HIV-1 infection, with CCR5 being the main coreceptor for macrophage-tropic strains. We have designed bifunctional fusion proteins, consisting of RANTES/CCL5 and a single-chain Fv Ab fragment against CD4 to simultaneously block CD4 and CCR5. The fusion proteins bind to both receptors, compete with RANTES/CCL5 binding, and induce down-modulation of CCR5 approximately 10 times more efficiently on CD4+ compared with CD8+ T cells. Moreover, after short incubation and subsequent washout, a significant down-modulation of CCR5 was only seen with the fusion proteins and only on CD4+ cells, but not with unmodified RANTES or on CD4- cells, indicating a preferential targeting of CCR5 on CD4+ T cells. The fusion proteins block M-tropic HIV infection more efficiently than RANTES/CCL5 and CD4 Abs alone or in combination. To our knowledge this is the first report of simultaneous blockade of an HIV-1 receptor and coreceptor with bifunctional inhibitors.
authors.affiliation: Klinikum, Department of Internal Medicine, University of Regensburg, Regensburg, Germany. mathias.mack@klinik.uni-regensburg.de
authors.forename: Matthias
authors.initials: M
authors.lastname: Mack
authors.forename: Jochen
authors.initials: J
authors.lastname: Pfirstinger
authors.forename: Jürgen
authors.initials: J
authors.lastname: Haas
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Nelson
authors.forename: Peter
authors.initials: P
authors.lastname: Kufer
authors.forename: Gert
authors.initials: G
authors.lastname: Riethmüller
authors.forename: Detlef
authors.initials: D
authors.lastname: Schlöndorff
mesh_terms: D000818:Animals; D001667:Binding, Competitive; D015704:CD4 Antigens / Q000276:immunology*; D016466:CHO Cells; D018946:Chemokine CCL5 / Q000276:immunology / Q000378:metabolism; D019742:Chemokines, CC / Q000276:immunology / Q000378:metabolism; D006224:Cricetinae; D005434:Flow Cytometry; D015658:HIV Infections / Q000517:prevention & control*; D015497:HIV-1 / Q000276:immunology; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000276:immunology; D019713:Receptors, CCR5 / Q000276:immunology*; D011993:Recombinant Fusion Proteins / Q000276:immunology* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013601:T-Lymphocytes / Q000276:immunology* / Q000821:virology
chemical_list: C483024:CCL5 protein, human; D015704:CD4 Antigens; D018946:Chemokine CCL5; D019742:Chemokines, CC; D007140:Immunoglobulin Fab Fragments; D019713:Receptors, CCR5; D011993:Recombinant Fusion Proteins