scholarly journals Anti-Human Immunodeficiency Virus Type 1 (HIV-1) Antibodies 2F5 and 4E10 Require Surprisingly Few Crucial Residues in the Membrane-Proximal External Region of Glycoprotein gp41 To Neutralize HIV-1

2005 ◽  
Vol 79 (2) ◽  
pp. 1252-1261 ◽  
Author(s):  
Michael B. Zwick ◽  
Richard Jensen ◽  
Sarah Church ◽  
Meng Wang ◽  
Gabriela Stiegler ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Alanine Scanning Mutagenesis ◽  
External Region ◽  
Membrane Proximal External Region ◽  
The Core ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT The conserved membrane-proximal external region (MPER) of human immunodeficiency virus type 1 (HIV-1) gp41 is a target of two broadly neutralizing human monoclonal antibodies, 2F5 and 4E10, and is an important lead for vaccine design. However, immunogens that bear MPER epitopes so far have not elicited neutralizing antibodies in laboratory animals. One explanation is that the immunogens fail to recreate the proper molecular environment in which the epitopes of 2F5 and 4E10 are presented on the virus. To explore this molecular environment, we used alanine-scanning mutagenesis across residues 660 to 680 in the MPER of a pseudotyped variant of HIV-1JR-FL, designated HIV-1JR2, and examined the ability of 2F5 and 4E10 to neutralize the Ala mutant viruses. The results show that the only changes to produce neutralization resistance to 2F5 occurred in residue D, K, or W of the core epitope (LELDKWANL). Likewise, 4E10 resistance arose by replacing one of three residues; two (W and F) were in the core epitope, and one (W) was seven residues C-terminal to these two (NWFDISNWLW). Importantly, no single substitution resulted in resistance of virus to both 2F5 and 4E10. Surprisingly, 8 out of 21 MPER Ala mutants were more sensitive than the parental pseudovirus to 2F5 and/or 4E10. At most, only small differences in neutralization sensitivity to anti-gp120 monoclonal antibody b12 and peptide T20 were observed with the MPER Ala mutant pseudoviruses. These data suggest that MPER substitutions can act locally and enhance the neutralizing activity of antibodies to this region and imply a distinct role of the MPER of gp41 during HIV-1 envelope-mediated fusion. Neutralization experiments showing synergy between and T20 and 4E10 against HIV-1 are also presented. The data presented may aid in the design of antigens that better present the MPER of gp41 to the immune system.

scholarly journals An Affinity-Enhanced Neutralizing Antibody against the Membrane-Proximal External Region of Human Immunodeficiency Virus Type 1 gp41 Recognizes an Epitope between Those of 2F5 and 4E10

2007 ◽  
Vol 81 (8) ◽  
pp. 4033-4043 ◽  
Author(s):  
Josh D. Nelson ◽  
Florence M. Brunel ◽  
Richard Jensen ◽  
Emma T. Crooks ◽  
Rosa M. F. Cardoso ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
External Region ◽  
Membrane Proximal External Region ◽  
High Affinity ◽  
Immunodeficiency Virus ◽  
Functional Envelope ◽  
Hiv 1

ABSTRACT The membrane-proximal external region (MPER) of human immunodeficiency virus type 1 (HIV-1) gp41 bears the epitopes of two broadly neutralizing antibodies (Abs), 2F5 and 4E10, making it a target for vaccine design. A third Ab, Fab Z13, had previously been mapped to an epitope that overlaps those of 2F5 and 4E10 but only weakly neutralizes a limited set of primary isolates. Here, libraries of Fab Z13 variants displayed on phage were engineered and affinity selected against an MPER peptide and recombinant gp41. A high-affinity variant, designated Z13e1, was isolated and found to be ∼100-fold improved over the parental Fab not only in binding affinity for the MPER antigens but also in neutralization potency against sensitive HIV-1. Alanine scanning of MPER residues 664 to 680 revealed that N671 and D674 are crucial for peptide recognition as well as for the neutralization of HIV-1 by Z13e1. Ab competition studies and truncation of MPER peptides indicate that Z13e1 binds with high affinity to an epitope between and overlapping with those of 2F5 and 4E10, with the minimal peptide epitope WASLWNWFDITN. Still, Z13e1 remained about an order of magnitude less potent than 4E10 against several isolates of pseudotyped HIV-1. The sum of our molecular analyses with Z13e1 suggests that the segment on the MPER of gp41 between the 2F5 and 4E10 epitopes is exposed on the functional envelope trimer but that access to the specific Z13e1 epitope within this segment is limited. Thus, the ability of MPER-bearing immunogens to elicit potent HIV-1-neutralizing Abs may depend in part on recapitulating the particular constraints that the functional envelope trimer imposes on the segment of the MPER to which Z13e1 binds.

scholarly journals Amino-Terminal Substitutions in the CCR5 Coreceptor Impair gp120 Binding and Human Immunodeficiency Virus Type 1 Entry

1998 ◽  
Vol 72 (1) ◽  
pp. 279-285 ◽  
Author(s):  
Tatjana Dragic ◽  
Alexandra Trkola ◽  
Steven W. Lin ◽  
Kirsten A. Nagashima ◽  
Francis Kajumo ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Surface Glycoprotein ◽  
Alanine Scanning Mutagenesis ◽  
Cc Chemokine ◽  
Amino Terminal ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT The CC-chemokine receptor CCR5 is required for the efficient fusion of macrophage (M)-tropic human immunodeficiency virus type 1 (HIV-1) strains with the plasma membrane of CD4+ cells and interacts directly with the viral surface glycoprotein gp120. Although receptor chimera studies have provided useful information, the domains of CCR5 that function for HIV-1 entry, including the site of gp120 interaction, have not been unambiguously identified. Here, we use site-directed, alanine-scanning mutagenesis of CCR5 to show that substitutions of the negatively charged aspartic acid residues at positions 2 and 11 (D2A and D11A) and a glutamic acid residue at position 18 (E18A), individually or in combination, impair or abolish CCR5-mediated HIV-1 entry for the ADA and JR-FL M-tropic strains and the DH123 dual-tropic strain. These mutations also impair Env-mediated membrane fusion and the gp120-CCR5 interaction. Of these three residues, only D11 is necessary for CC-chemokine-mediated inhibition of HIV-1 entry, which is, however, also dependent on other extracellular CCR5 residues. Thus, the gp120 and CC-chemokine binding sites on CCR5 are only partially overlapping, and the former site requires negatively charged residues in the amino-terminal CCR5 domain.

scholarly journals 4E10-Resistant Variants in a Human Immunodeficiency Virus Type 1 Subtype C-Infected Individual with an Anti-Membrane-Proximal External Region-Neutralizing Antibody Response

2007 ◽  
Vol 82 (5) ◽  
pp. 2367-2375 ◽  
Author(s):  
Elin S. Gray ◽  
Penny L. Moore ◽  
Frederic Bibollet-Ruche ◽  
Hui Li ◽  
Julie M. Decker ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Antibody Response ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Neutralizing Antibody ◽  
Subtype C ◽  
External Region ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT The broadly neutralizing monoclonal antibody (MAb) 4E10 recognizes a linear epitope in the C terminus of the membrane-proximal external region (MPER) of gp41. This epitope is particularly attractive for vaccine design because it is highly conserved among human immunodeficiency virus type 1 (HIV-1) strains and neutralization escape in vivo has not been observed. Multiple env genes were cloned from an HIV-1 subtype C virus isolated from a 7-year-old perinatally infected child who had anti-MPER neutralizing antibodies. One clone (TM20.13) was resistant to 4E10 neutralization as a result of an F673L substitution in the MPER. Frequency analysis showed that F673L was present in 33% of the viral variants and in all cases was linked to the presence of an intact 2F5 epitope. Two other envelope clones were sensitive to 4E10 neutralization, but TM20.5 was 10-fold less sensitive than TM20.6. Substitutions at positions 674 and 677 within the MPER rendered TM20.5 more sensitive to 4E10 but had no effect on TM20.6. Using chimeric and mutant constructs of these two variants, we further demonstrated that the lentivirus lytic peptide-2 domain in the cytoplasmic tail affected the accessibility of the 4E10 epitope, as well as virus infectivity. Collectively, these genetic changes in the face of a neutralizing antibody response to the MPER strongly suggested immune escape from antibody responses targeting this region.

scholarly journals Broad Neutralization of Human Immunodeficiency Virus Type 1 (HIV-1) Elicited from Human Rhinoviruses That Display the HIV-1 gp41 ELDKWA Epitope

2009 ◽  
Vol 83 (10) ◽  
pp. 5087-5100 ◽  
Author(s):  
Gail Ferstandig Arnold ◽  
Paola K. Velasco ◽  
Andrew K. Holmes ◽  
Terri Wrin ◽  
Sheila C. Geisler ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Human Monoclonal Antibody ◽  
Combinatorial Libraries ◽  
External Region ◽  
Aids Vaccine ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT In efforts to develop AIDS vaccine components, we generated combinatorial libraries of recombinant human rhinoviruses that display the well-conserved ELDKWA epitope of the membrane-proximal external region of human immunodeficiency virus type 1 (HIV-1) gp41. The broadly neutralizing human monoclonal antibody 2F5 was used to select for viruses whose ELDKWA conformations resemble those of HIV. Immunization of guinea pigs with different chimeras, some boosted with ELDKWA-based peptides, elicited antibodies capable of neutralizing HIV-1 pseudoviruses of diverse subtypes and coreceptor usages. These recombinant immunogens are the first reported that elicit broad, albeit modest, neutralization of HIV-1 using an ELDKWA-based epitope and are among the few reported that elicit broad neutralization directed against any recombinant HIV epitope, providing a critical advance in developing effective AIDS vaccine components.

scholarly journals The Membrane-Proximal External Region of the Human Immunodeficiency Virus Type 1 Envelope: Dominant Site of Antibody Neutralization and Target for Vaccine Design

2008 ◽  
Vol 72 (1) ◽  
pp. 54-84 ◽  
Author(s):  
Marinieve Montero ◽  
Nienke E. van Houten ◽  
Xin Wang ◽  
Jamie K. Scott
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Neutralizing Antibodies ◽  
Vaccine Design ◽  
Broadly Neutralizing Antibodies ◽  
External Region ◽  
Membrane Proximal External Region ◽  
Immunodeficiency Virus

SUMMARY Enormous efforts have been made to produce a protective vaccine against human immunodeficiency virus type 1; there has been little success. However, the identification of broadly neutralizing antibodies against epitopes on the highly conserved membrane-proximal external region (MPER) of the gp41 envelope protein has delineated this region as an attractive vaccine target. Furthermore, emerging structural information on the MPER has provided vaccine designers with new insights for building relevant immunogens. This review describes the current state of the field regarding (i) the structure and function of the gp41 MPER; (ii) the structure and binding mechanisms of the broadly neutralizing antibodies 2F5, 4E10, and Z13; and (iii) the development of an MPER-targeting vaccine. In addition, emerging approaches to vaccine design are presented.

scholarly journals Subdomain Folding and Biological Activity of the Core Structure from Human Immunodeficiency Virus Type 1 gp41: Implications for Viral Membrane Fusion

1999 ◽  
Vol 73 (5) ◽  
pp. 4433-4438 ◽  
Author(s):  
Min Lu ◽  
Hong Ji ◽  
Steven Shen
Keyword(s):  
Human Immunodeficiency Virus ◽  
Membrane Fusion ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Covalent Attachment ◽  
Direct Role ◽  
The Core ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT The envelope glycoprotein of human immunodeficiency virus type 1 (HIV-1) consists of two subunits, gp120 and gp41. The extraviral portion (ectodomain) of gp41 contains an α-helical domain that likely represents the core of the fusion-active conformation of the molecule. Here we report the identification and characterization of a minimal, autonomous folding subdomain that retains key determinants in specifying the overall fold of the gp41 ectodomain core. This subdomain, designated N34(L6)C28, is formed by covalent attachment of peptides N-34 and C-28 by a short flexible linker in place of the normal disulfide-bonded loop sequence. N34(L6)C28 forms a highly thermostable, α-helical trimer. Point mutations within the envelope protein complex that abolish membrane fusion and HIV-1 infectivity also impede the formation of the N34(L6)C28 core. Moreover, N34(L6)C28 is capable of inhibiting HIV-1 envelope-mediated membrane fusion. Taken together, these results indicate that the N34(L6)C28 core plays a direct role in the membrane fusion step of HIV-1 infection and thus provides a molecular target for the development of antiviral pharmaceutical agents.

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