title: The Effects of the Recombinant CCR5 T4 Lysozyme Fusion Protein on HIV-1 Infection.
abstract: BACKGROUND
  Insertion of T4 lysozyme (T4L) into the GPCR successfully enhanced GPCR protein stability and solubilization. However, the biological functions of the recombinant GPCR protein have not been analyzed.
  
  
  METHODS
  We engineered the CCR5-T4L mutant and expressed and purified the soluble recombinant protein using an E.coli expression system. The antiviral effects of this recombinant protein in THP-1 cell lines, primary human macrophages, and PBMCs from different donors were investigated. We also explored the possible mechanisms underlying the observed antiviral effects.
  
  
  RESULTS
  Our data showed the biphasic inhibitory and promotion effects of different concentrations of soluble recombinant CCR5-T4L protein on R5 tropic human immunodeficiency virus-1 (HIV-1) infection in THP-1 cell lines, human macrophages, and PBMCs from clinical isolates. We demonstrated that soluble recombinant CCR5-T4L acts as a HIV-1 co-receptor, interacts with wild type CCR5, down-regulates the surface CCR5 expression in human macrophages, and interacts with CCL5 to inhibit macrophage migration. Using binding assays, we further determined that recombinant CCR5-T4L and [125I]-CCL5 compete for the same binding site on wild type CCR5.
  
  
  CONCLUSIONS
  Our results suggest that recombinant CCR5-T4L protein marginally promotes HIV-1 infection at low concentrations and markedly inhibits infection at higher concentrations. This recombinant protein may be helpful in the future development of anti-HIV-1 therapeutic agents.
authors.affiliation: Department of Microbiology and Immunology, Nanjing Medical University, 140 Hanzhong Road, Nanjing, Jiangsu Province, China; Department of Neurology, The People's Hospital of Jiangsu Province, 300 Guangzhou Road, Nanjing, Jiangsu Province, China; Department of Neurology, Nanjing First Hospital, 68 Changle Road, Nanjing, Jiangsu Province, China.
authors.forename: Qingwen
authors.initials: Q
authors.lastname: Jin
authors.affiliation: Department of Neurology, The People's Hospital of Jiangsu Province, 300 Guangzhou Road, Nanjing, Jiangsu Province, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Chen
authors.affiliation: Department of Neurology, The People's Hospital of Jiangsu Province, 300 Guangzhou Road, Nanjing, Jiangsu Province, China.
authors.forename: Xingxia
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Neurology, The Second Hospital of Huaian, 62 Huaihai South Road, Huaian, Jiangsu Province, China.
authors.forename: Liandong
authors.initials: L
authors.lastname: Zhao
authors.affiliation: Department of Neurology, Nanjing First Hospital, 68 Changle Road, Nanjing, Jiangsu Province, China.
authors.forename: Qingchen
authors.initials: Q
authors.lastname: Xu
authors.affiliation: Department of Microbiology and Immunology, Nanjing Medical University, 140 Hanzhong Road, Nanjing, Jiangsu Province, China.
authors.forename: Huijuan
authors.initials: H
authors.lastname: Wang
authors.affiliation: Department of Neurology, Mingji Hospital of Nanjing, Jiangsu Province, 71 Riverside West Road, Nanjing, Jiangsu Province, China.
authors.forename: Guanyu
authors.initials: G
authors.lastname: Li
authors.affiliation: Department of Microbiology and Immunology, Nanjing Medical University, 140 Hanzhong Road, Nanjing, Jiangsu Province, China.
authors.forename: Xiaofan
authors.initials: X
authors.lastname: Yang
authors.affiliation: Department of Biomedical Sciences, Texas Tech University Health Sciences Center, 5001 El Paso Drive, El Paso, Texas, United States of America.
authors.forename: Hongming
authors.initials: H
authors.lastname: Ma
authors.affiliation: Department of Biomedical Sciences, Texas Tech University Health Sciences Center, 5001 El Paso Drive, El Paso, Texas, United States of America.
authors.forename: Haoquan
authors.initials: H
authors.lastname: Wu
authors.affiliation: Department of Microbiology and Immunology, Nanjing Medical University, 140 Hanzhong Road, Nanjing, Jiangsu Province, China.
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Ji
mesh_terms: D016475:3T3 Cells; D000818:Animals; D000998:Antiviral Agents / Q000494:pharmacology; D017122:Bacteriophage T4 / Q000201:enzymology*; D002460:Cell Line; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002465:Cell Movement / Q000187:drug effects; D018946:Chemokine CCL5 / Q000494:pharmacology; D002630:Chemotactic Factors / Q000494:pharmacology; D015536:Down-Regulation / Q000187:drug effects; D004926:Escherichia coli / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000378:metabolism; D015658:HIV Infections / Q000188:drug therapy* / Q000473:pathology / Q000821:virology; D015497:HIV-1 / Q000187:drug effects; D006801:Humans; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism / Q000821:virology; D051379:Mice; D009000:Monocytes / Q000473:pathology; D009113:Muramidase / Q000378:metabolism*; D011485:Protein Binding / Q000187:drug effects; D019713:Receptors, CCR5 / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000302:isolation & purification / Q000494:pharmacology / Q000627:therapeutic use*; D012995:Solubility; D014019:Tissue Donors; D056189:Viral Tropism / Q000187:drug effects; D014779:Virus Replication / Q000187:drug effects
chemical_list: D000998:Antiviral Agents; D018946:Chemokine CCL5; D002630:Chemotactic Factors; D019713:Receptors, CCR5; D011993:Recombinant Fusion Proteins; D009113:Muramidase; D019204:GTP-Binding Proteins