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A Global Neutralization Resistance Phenotype of Human Immunodeficiency Virus Type 1 Is Determined by Distinct Mechanisms Mediating Enhanced Infectivity and Conformational Change of the Envelope Complex

A Global Neutralization Resistance Phenotype of Human Immunodeficiency Virus Type 1 Is Determined... A Global Neutralization Resistance Phenotype of Human Immunodeficiency Virus Type 1 Is Determined by Distinct Mechanisms Mediating Enhanced Infectivity and Conformational Change of the Envelope Complex Eun Ju Park 1 , Miroslav K. Gorny 2 , Susan Zolla-Pazner 2 , 3 , and Gerald V. Quinnan Jr. 1 , * Department of Preventive Medicine and Biometrics, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814 1 ; New York University School of Medicine, New York, New York 10016 2 ; and Research Center for AIDS and HIV Infection, Veterans Affairs Medical Center, New York, New York 10010 3 ABSTRACT We have described previously genetic characterization of neutralization-resistant, high-infectivity, and neutralization-sensitive, low-infectivity mutants of human immunodeficiency virus type 1 (HIV-1) MN envelope. The distinct phenotypes of these clones are attributable to six mutations affecting functional interactions between the gp120 C4-V5 regions and the gp41 leucine zipper. In the present study we examined mechanisms responsible for the phenotypic differences between these envelopes using neutralization and immunofluorescence assays (IFA). Most monoclonal antibodies (MAbs) tested against gp120 epitopes (V3, CD4 binding site, and CD4-induced) were 20 to 100 times more efficient at neutralizing pseudovirus expressing sensitive rather than resistant envelope. By IFA cells expressing neutralization sensitive envelope bound MAbs to gp120 epitopes more, but gp41 epitopes less, than neutralization-resistant envelope. This binding difference appeared to reflect conformational change, since it did not correlate with the level of protein expression or gp120-gp41 dissociation. This conformational change was mostly attributable to one mutation, L544P, which contributes to neutralization resistance but not to infectivity enhancement. The V420I mutation, which contributes a major effect to both high infectivity and neutralization resistance, had no apparent effect on conformation. Notably, a conformation-dependent V3 neutralization epitope remained sensitive to neutralization and accessible to binding by MAbs on neutralization-resistant HIV-1 envelope. Sensitivity to sCD4 did not distinguish the clones, suggesting that the phenotypes may be related to post-CD4-binding effects. The results demonstrate that neutralization resistance can be determined by distinguishable effects of mutations, which cause changes in envelope conformation and/or function(s) related to infectivity. A conformation-dependent V3 epitope may be an important target for neutralization of resistant strains of HIV-1. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Journal of Virology American Society For Microbiology

A Global Neutralization Resistance Phenotype of Human Immunodeficiency Virus Type 1 Is Determined by Distinct Mechanisms Mediating Enhanced Infectivity and Conformational Change of the Envelope Complex

A Global Neutralization Resistance Phenotype of Human Immunodeficiency Virus Type 1 Is Determined by Distinct Mechanisms Mediating Enhanced Infectivity and Conformational Change of the Envelope Complex

Journal of Virology , Volume 74 (9): 4183 – May 1, 2000

Abstract

A Global Neutralization Resistance Phenotype of Human Immunodeficiency Virus Type 1 Is Determined by Distinct Mechanisms Mediating Enhanced Infectivity and Conformational Change of the Envelope Complex Eun Ju Park 1 , Miroslav K. Gorny 2 , Susan Zolla-Pazner 2 , 3 , and Gerald V. Quinnan Jr. 1 , * Department of Preventive Medicine and Biometrics, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814 1 ; New York University School of Medicine, New York, New York 10016 2 ; and Research Center for AIDS and HIV Infection, Veterans Affairs Medical Center, New York, New York 10010 3 ABSTRACT We have described previously genetic characterization of neutralization-resistant, high-infectivity, and neutralization-sensitive, low-infectivity mutants of human immunodeficiency virus type 1 (HIV-1) MN envelope. The distinct phenotypes of these clones are attributable to six mutations affecting functional interactions between the gp120 C4-V5 regions and the gp41 leucine zipper. In the present study we examined mechanisms responsible for the phenotypic differences between these envelopes using neutralization and immunofluorescence assays (IFA). Most monoclonal antibodies (MAbs) tested against gp120 epitopes (V3, CD4 binding site, and CD4-induced) were 20 to 100 times more efficient at neutralizing pseudovirus expressing sensitive rather than resistant envelope. By IFA cells expressing neutralization sensitive envelope bound MAbs to gp120 epitopes more, but gp41 epitopes less, than neutralization-resistant envelope. This binding difference appeared to reflect conformational change, since it did not correlate with the level of protein expression or gp120-gp41 dissociation. This conformational change was mostly attributable to one mutation, L544P, which contributes to neutralization resistance but not to infectivity enhancement. The V420I mutation, which contributes a major effect to both high infectivity and neutralization resistance, had no apparent effect on conformation. Notably, a conformation-dependent V3 neutralization epitope remained sensitive to neutralization and accessible to binding by MAbs on neutralization-resistant HIV-1 envelope. Sensitivity to sCD4 did not distinguish the clones, suggesting that the phenotypes may be related to post-CD4-binding effects. The results demonstrate that neutralization resistance can be determined by distinguishable effects of mutations, which cause changes in envelope conformation and/or function(s) related to infectivity. A conformation-dependent V3 epitope may be an important target for neutralization of resistant strains of HIV-1.

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References (40)

Publisher
American Society For Microbiology
Copyright
Copyright © 2000 by the American society for Microbiology.
ISSN
0022-538X
eISSN
1098-5514
DOI
10.1128/JVI.74.9.4183-4191.2000
Publisher site
See Article on Publisher Site

Abstract

A Global Neutralization Resistance Phenotype of Human Immunodeficiency Virus Type 1 Is Determined by Distinct Mechanisms Mediating Enhanced Infectivity and Conformational Change of the Envelope Complex Eun Ju Park 1 , Miroslav K. Gorny 2 , Susan Zolla-Pazner 2 , 3 , and Gerald V. Quinnan Jr. 1 , * Department of Preventive Medicine and Biometrics, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814 1 ; New York University School of Medicine, New York, New York 10016 2 ; and Research Center for AIDS and HIV Infection, Veterans Affairs Medical Center, New York, New York 10010 3 ABSTRACT We have described previously genetic characterization of neutralization-resistant, high-infectivity, and neutralization-sensitive, low-infectivity mutants of human immunodeficiency virus type 1 (HIV-1) MN envelope. The distinct phenotypes of these clones are attributable to six mutations affecting functional interactions between the gp120 C4-V5 regions and the gp41 leucine zipper. In the present study we examined mechanisms responsible for the phenotypic differences between these envelopes using neutralization and immunofluorescence assays (IFA). Most monoclonal antibodies (MAbs) tested against gp120 epitopes (V3, CD4 binding site, and CD4-induced) were 20 to 100 times more efficient at neutralizing pseudovirus expressing sensitive rather than resistant envelope. By IFA cells expressing neutralization sensitive envelope bound MAbs to gp120 epitopes more, but gp41 epitopes less, than neutralization-resistant envelope. This binding difference appeared to reflect conformational change, since it did not correlate with the level of protein expression or gp120-gp41 dissociation. This conformational change was mostly attributable to one mutation, L544P, which contributes to neutralization resistance but not to infectivity enhancement. The V420I mutation, which contributes a major effect to both high infectivity and neutralization resistance, had no apparent effect on conformation. Notably, a conformation-dependent V3 neutralization epitope remained sensitive to neutralization and accessible to binding by MAbs on neutralization-resistant HIV-1 envelope. Sensitivity to sCD4 did not distinguish the clones, suggesting that the phenotypes may be related to post-CD4-binding effects. The results demonstrate that neutralization resistance can be determined by distinguishable effects of mutations, which cause changes in envelope conformation and/or function(s) related to infectivity. A conformation-dependent V3 epitope may be an important target for neutralization of resistant strains of HIV-1.

Journal

Journal of VirologyAmerican Society For Microbiology

Published: May 1, 2000

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