title: Insertion of primary syncytium-inducing (SI) and non-SI envelope V3 loops in human immunodeficiency virus type 1 (HIV-1) LAI reduces neutralization sensitivity to autologous, but not heterologous, HIV-1 antibodies.
abstract: The aim of the study was to investigate the influence of V3 loops from naturally occurring viruses on the neutralization sensitivity of a molecularly cloned virus. A selection of well-defined syncytium-inducing (SI) and non-SI V3 loops of a single human immunodeficiency virus type 1-infected individual (H594) and the V3 regions of two SI laboratory strains were inserted in an infectious molecular clone of human immunodeficiency type 1 LAI. Neutralization was performed with a heterologous serum pool and autologous patient serum, using the virus reduction neutralization assay and peripheral blood lymphocytes as target cells. High sensitivity of the chimeric viruses containing the laboratory strain V3 regions to neutralization by H594 sequential sera as well as the heterologous serum pool was found. A statistically significant correlation between the sensitivities of these viruses was seen. In contrast, insertion of the primary isolate NSI and SI envelope V3 loops significantly reduced the neutralization by autologous serum but not by the heterologous serum pool. No correlation was found between the neutralization of the viruses with laboratory strain-derived V3 regions and the viruses with primary isolate V3 domains. We conclude that heterologous antibodies are able to neutralize infectious molecular clones with V3 loops of both SI and NSI viruses, regardless of whether they originated from laboratory strains or primary isolates. However, serum of patient H594 discriminated between the two types of viruses and showed reduced neutralization of the viruses with the autologous NSI and SI primary isolate V3 loops. These results indicated that the neutralization sensitivity of the viruses depended on the capacity of the V3 region to influence the conformation of the virus envelope. These V3-dependent conformational changes partially explain the neutralization sensitivity of laboratory strains and the relative neutralization resistance of primary isolates.
authors.affiliation: Human Retrovirus Laboratory, Academic Medical Center, University of Amsterdam, The Netherlands.
authors.forename: E
authors.initials: E
authors.lastname: Hogervorst
authors.forename: J
authors.initials: J
authors.lastname: de Jong
authors.forename: A
authors.initials: A
authors.lastname: van Wijk
authors.forename: M
authors.initials: M
authors.lastname: Bakker
authors.forename: M
authors.initials: M
authors.lastname: Valk
authors.forename: P
authors.initials: P
authors.lastname: Nara
authors.forename: J
authors.initials: J
authors.lastname: Goudsmit
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000821:virology; D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D016384:Consensus Sequence; D015686:Gene Products, env / Q000096:biosynthesis* / Q000276:immunology*; D015726:Giant Cells; D015483:HIV Antibodies / Q000276:immunology*; D015488:HIV Antigens / Q000276:immunology*; D015497:HIV-1 / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D018451:Homosexuality, Male; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D008297:Male; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D009500:Neutralization Tests; D010641:Phenotype; D016133:Polymerase Chain Reaction; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000276:immunology; D015183:Restriction Mapping; D012680:Sensitivity and Specificity; D014779:Virus Replication
chemical_list: D015686:Gene Products, env; D015483:HIV Antibodies; D015488:HIV Antigens; D007074:Immunoglobulin G; D011993:Recombinant Fusion Proteins