title: Liposome targeting to human immunodeficiency virus type 1-infected cells via recombinant soluble CD4 and CD4 immunoadhesin (CD4-IgG).
abstract: HIV-infected cells producing virions express the viral envelope glycoprotein gp120/gp41 on their surface. We examined whether liposomes coupled to recombinant soluble CD4 (sCD4, the ectodomain of CD4 which binds gp120 with high affinity) could specifically bind to HIV-infected cells. sCD4 was chemically coupled by 2 different methods to liposomes containing rhodamine-phosphatidylethanolamine in their membrane as a fluorescent marker. In one method, sCD4 was thiolated with N-succinimidyl acetylthioacetate (SATA) and coupled to liposomes via a maleimide-derivatised phospholipid. In the other method, the oligosaccharides on sCD4 were coupled to a sulfhydryl-derivatised phospholipid, utilizing the bifunctional reagent, 4-(4-N-maleimidophenyl)butyric acid hydrazide (MPBH). The association of the liposomes with HIV-1-infected or uninfected cells was examined by flow cytometry. CD4-coupled liposomes associated specifically to chronically infected H9/HTLV-IIIB cells, but not to uninfected H9 cells. CD4-coupled liposomes also associated specifically with monocytic THP-1 cells chronically infected with HIV-1 (THP-1/HIV-1IIIB). Control liposomes without coupled CD4 did not associate significantly with any of the cells, while free sCD4 could competitively inhibit the association of the CD4-coupled liposomes with the infected cells. The chimeric molecule CD4-immunoadhesin (CD4-IgG) could also be used as a ligand to target liposomes with covalently coupled Protein A (which binds the Fc region of the CD4-IgG) to H9/HTLV-IIIB cells. The CD4-liposomes inhibited the infectivity of HIV-1 in A3.01 cells, and also bound rgp120. Our results suggest that liposomes containing antiviral or cytotoxic agents may be targeted specifically to HIV-infected cells.
authors.affiliation: Department of Microbiology, School of Dentistry, University of the Pacific, San Francisco, CA 94115-2399.
authors.forename: D
authors.initials: D
authors.lastname: Flasher
authors.forename: K
authors.initials: K
authors.lastname: Konopka
authors.forename: S M
authors.initials: SM
authors.lastname: Chamow
authors.forename: P
authors.initials: P
authors.lastname: Dazin
authors.forename: A
authors.initials: A
authors.lastname: Ashkenazi
authors.forename: E
authors.initials: E
authors.lastname: Pretzer
authors.forename: N
authors.initials: N
authors.lastname: Düzgünes
mesh_terms: D015704:CD4 Antigens / Q000276:immunology / Q000494:pharmacology*; D016860:CD4 Immunoadhesins / Q000494:pharmacology*; D002461:Cell Line, Transformed; D004337:Drug Carriers; D005434:Flow Cytometry; D015699:HIV Envelope Protein gp120 / Q000276:immunology; D015497:HIV-1 / Q000276:immunology / Q000472:pathogenicity*; D006801:Humans; D008081:Liposomes / Q000737:chemistry* / Q000276:immunology; D013205:Staphylococcal Protein A / Q000494:pharmacology; D014774:Virulence
chemical_list: D015704:CD4 Antigens; D016860:CD4 Immunoadhesins; D004337:Drug Carriers; D015699:HIV Envelope Protein gp120; D008081:Liposomes; D013205:Staphylococcal Protein A