scholarly journals Alterations in the Immunogenic Properties of Soluble Trimeric Human Immunodeficiency Virus Type 1 Envelope Proteins Induced by Deletion or Heterologous Substitutions of the V1 Loop

2010 ◽  
Vol 84 (19) ◽  
pp. 9932-9946 ◽  
Author(s):  
Lance Ching ◽  
Leonidas Stamatatos
Keyword(s):  
Neutralizing Antibodies ◽  
Hypervariable Region ◽  
Immunodeficiency Virus ◽  
Cd4 Binding Site ◽  
Gp140 Envelope ◽  
The Common ◽  
Immunogenic Properties ◽  
Hiv 1 ◽  
High Immunogenicity

ABSTRACT HIV-1 gp140 envelope immunogens express conserved epitopes that are targeted by broadly cross-reactive neutralizing antibodies, but they fail to elicit similar antibodies upon immunization. The poor immunogenicity of conserved epitopes on gp140 could be linked to the high immunogenicity of variable Env regions on such constructs. Previous studies have shown that the first hypervariable region (V1 loop) is immunogenic on soluble gp140s but elicits type-specific antibodies. To address issues related to the high immunogenicity of the V1 loop, two conceptually opposite approaches were tested. In the first approach, we eliminated the V1 loop from our gp140 construct and examined how V1 deletion altered the immunogenic properties of other Env regions. In the second approach, we took advantage of the high immunogenicity of the V1 loop and engrafted four diverse V1 loops onto a common gp140 Env “scaffold.” These four scaffolds were used as a cocktail of immunogens to elicit diverse anti-V1 antibodies, under the hypothesis that eliciting diverse anti-V1 antibodies would expand the neutralizing breadth of immune sera. Our study indicates that three of four heterologous V1 loops were immunogenic on the common Env backbone “scaffold,” but heterologous anti-V1 neutralizing responses were observed in only one case. Both types of V1 modification dampened the immunogenicity of the V3 loop, differentially altered the immunogenicity of the transmembrane gp41 subunit, and altered the relative immunogenicities of unknown Env regions, including potentially the CD4-binding site (CD4-bs) and trimer-specific targets, which elicited cross-reactive neutralizing antibodies but of limited breadth.

scholarly journals The Ability of an Oligomeric Human Immunodeficiency Virus Type 1 (HIV-1) Envelope Antigen To Elicit Neutralizing Antibodies against Primary HIV-1 Isolates Is Improved following Partial Deletion of the Second Hypervariable Region

2001 ◽  
Vol 75 (12) ◽  
pp. 5526-5540 ◽  
Author(s):  
S. W. Barnett ◽  
S. Lu ◽  
I. Srivastava ◽  
S. Cherpelis ◽  
A. Gettie ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Neutralizing Antibodies ◽  
Rhesus Macaques ◽  
Hypervariable Region ◽  
Partial Deletion ◽  
Clade B ◽  
Immunodeficiency Virus ◽  
Two Envelopes ◽  
Hiv 1

ABSTRACT Partial deletion of the second hypervariable region from the envelope of the primary-like SF162 virus increases the exposure of certain neutralization epitopes and renders the virus, SF162ΔV2, highly susceptible to neutralization by clade B and non-clade B human immunodeficiency virus (HIV-positive) sera (L. Stamatatos and C. Cheng-Mayer, J. Virol. 78:7840–7845, 1998). This observation led us to propose that the modified, SF162ΔV2-derived envelope may elicit higher titers of cross-reactive neutralizing antibodies than the unmodified SF162-derived envelope. To test this hypothesis, we immunized rabbits and rhesus macaques with the gp140 form of these two envelopes. In rabbits, both immunogens elicited similar titers of binding antibodies but the modified immunogen was more effective in eliciting neutralizing antibodies, not only against the SF162ΔV2 and SF162 viruses but also against several heterologous primary HIV type 1 (HIV-1) isolates. In rhesus macaques both immunogens elicited potent binding antibodies, but again the modified immunogen was more effective in eliciting the generation of neutralizing antibodies against the SF162ΔV2 and SF162 viruses. Antibodies capable of neutralizing several, but not all, heterologous primary HIV-1 isolates tested were elicited only in macaques immunized with the modified immunogen. The efficiency of neutralization of these heterologous isolates was lower than that recorded against the SF162 isolate. Our results strongly suggest that although soluble oligomeric envelope subunit vaccines may elicit neutralizing antibody responses against heterologous primary HIV-1 isolates, these responses will not be broad and potent unless specific modifications are introduced to increase the exposure of conserved neutralization epitopes.

scholarly journals Changes in the Immunogenic Properties of Soluble gp140 Human Immunodeficiency Virus Envelope Constructs upon Partial Deletion of the Second Hypervariable Region

2003 ◽  
Vol 77 (4) ◽  
pp. 2310-2320 ◽  
Author(s):  
Indresh K. Srivastava ◽  
Keating VanDorsten ◽  
Lucia Vojtech ◽  
Susan W. Barnett ◽  
Leonidas Stamatatos
Keyword(s):  
Human Immunodeficiency Virus ◽  
Binding Site ◽  
Hypervariable Region ◽  
V3 Loop ◽  
Virus Envelope ◽  
Immunodeficiency Virus ◽  
Cd4 Binding Site ◽  
Hiv Envelope ◽  
Immunogenic Properties ◽  
Hiv 1

ABSTRACT Immunization of macaques with the soluble oligomeric gp140 form of the SF162 envelope (SF162gp140) or with an SF162gp140-derived construct lacking the central region of the V2 loop (ΔV2gp140) results in the generation of high titers of antibodies capable of neutralizing the homologous human immunodeficiency virus type 1 (HIV-1), SF162 virus (Barnett et al. J. Virol. 75 :5526-5540, 2001). However, the ΔV2gp140 immunogen is more effective than the SF162gp140 immunogen in eliciting the generation of antibodies capable of neutralizing heterologous HIV-1 isolates. This indicates that deletion of the V2 loop alters the immunogenicity of the SF162gp140 protein. The present studies were aimed at identifying the envelope regions whose immunogenicity is altered following V2 loop deletion. We report that the antibodies elicited by the SF162gp140 immunogen recognize elements of the V1, V2, and V3 loops, the CD4-binding site, and the C1 and C2 regions on the homologous SF162 gp120. With the exception of the V1 and V2 loops, the same regions are recognized on heterologous gp120 proteins. Surprisingly, although a minority of the SF162gp140-elicited antibodies target the V3 loop on the homologous gp120, the majority of the antibodies elicited by this immunogen that are capable of binding to the heterologous gp120s tested recognize their V3 loops. Deletion of the V2 loop has two effects. First, it alters the immunogenicity of the V3 and V1 loops, and second, it renders the C5 region immunogenic. Although deletion of the V2 loop does not result in an increase in the immunogenicity of the CD4-binding site per se, the relative ratio of anti-CD4-binding site to anti-V3 loop antibodies that bind to the heterologous gp120s tested is higher in sera collected from the ΔV2gp140-immunized animals than in the SF162gp140-immunized animals. Overall, our studies indicate that it is possible to alter the immunogenic structure of the HIV envelope by introducing specific modifications.

scholarly journals Mechanism of Human Immunodeficiency Virus Type 1 Resistance to Monoclonal Antibody b12 That Effectively Targets the Site of CD4 Attachment

2009 ◽  
Vol 83 (21) ◽  
pp. 10892-10907 ◽  
Author(s):  
Xueling Wu ◽  
Tongqing Zhou ◽  
Sijy O'Dell ◽  
Richard T. Wyatt ◽  
Peter D. Kwong ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Binding Site ◽  
Contact Surface ◽  
Neutralizing Antibodies ◽  
Viral Envelope ◽  
Contact Sites ◽  
Immunodeficiency Virus ◽  
Cd4 Binding Site ◽  
Hiv 1

ABSTRACT The region of the human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein gp120 that engages its primary cellular receptor CD4 forms a site of vulnerability to neutralizing antibodies. The monoclonal antibody b12 exploits the conservation and accessibility of the CD4-binding site to neutralize many, though not all, HIV-1 isolates. To understand the basis of viral resistance to b12, we used the atomic-level definition of b12-gp120 contact sites to study a panel of diverse circulating viruses. A combination of sequence analysis, computational modeling, and site-directed mutagenesis was used to determine the influence of amino acid variants on binding and neutralization by b12. We found that several substitutions within the dominant b12 contact surface, called the CD4-binding loop, mediated b12 resistance, and that these substitutions resided just proximal to the known CD4 contact surface. Hence, viruses varied in key b12 contact residues that are proximal to, but not part of, the CD4 contact surface. This explained how viral isolates were able to evade b12 neutralization while maintaining functional binding to CD4. In addition, some viruses were resistant to b12 despite minimal sequence variation at b12 contact sites. Such neutralization resistance usually could be reversed by alterations at residues thought to influence the quaternary configuration of the viral envelope spike. To design immunogens that elicit neutralizing antibodies directed to the CD4-binding site, researchers need to address the antigenic variation within this region of gp120 and the restricted access to the CD4-binding site imposed by the native configuration of the trimeric viral envelope spike.

scholarly journals Rational engraftment of quaternary-interactive acidic loops for anti-HIV-1 antibody improvement

2021 ◽  
Author(s):  
Qingbo Liu ◽  
Peng Zhang ◽  
Huiyi Miao ◽  
Yin Lin ◽  
Young Do Kwon ◽  
...  
Keyword(s):  
Binding Site ◽  
Neutralizing Antibodies ◽  
Receptor Binding Site ◽  
Neutralizing Capacity ◽  
Immunodeficiency Virus ◽  
Cd4 Binding Site ◽  
Binding Antibody ◽  
Novel Strategy ◽  
Hiv 1

Broadly neutralizing antibodies (bNAbs) are the focus of increasing interest for human immunodeficiency virus type-1 (HIV-1) prevention and treatment. Although several bNAbs are already under clinical evaluation, the development of antibodies with even greater potency and breadth remains a priority. Recently, we reported a novel strategy for improving bNAbs against the CD4-binding site (CD4bs) of gp120 by engraftment of the elongated framework region 3 (FR3) from VRC03, which confers the ability to establish quaternary interactions with a second gp120 protomer. Here, we applied this strategy to a new series of anti-CD4bs bNAbs (N49 lineage) that already possess high potency and breadth. The resultant chimeric antibodies bind the HIV-1 envelope (Env) trimer with a higher affinity than their parental forms. Likewise, their neutralizing capacity against a global panel of HIV-1 Envs is also increased. The introduction of additional modifications further improved the neutralization potency. We also tried engrafting the elongated CDR1 of the heavy chain (CDRH1) from bNAb 1-18, another highly potent quaternary-binding antibody, onto several VRC01-class bNAbs, but none of them was improved. These findings point to the highly selective requirements for the establishment of quaternary contact with the HIV-1 Env trimer. The improved anti-CD4bs antibodies reported herein may provide a helpful complement to current antibody-based protocols for the therapy and prevention of HIV-1 infection. IMPORTANCE Monoclonal antibodies represent one of the most important recent innovations in the fight against infectious diseases. Although potent antibodies can be cloned from infected individuals, various strategies can be employed to improve their activity or pharmacological features. Here, we improved a lineage of very potent antibodies that target the receptor-binding site of HIV-1 by engineering chimeric molecules containing a fragment from a different monoclonal antibody. These engineered antibodies are promising candidates for development of therapeutic or preventive approaches against HIV/AIDS.

scholarly journals Enhanced Exposure of the CD4-Binding Site to Neutralizing Antibodies by Structural Design of a Membrane-Anchored Human Immunodeficiency Virus Type 1 gp120 Domain

2009 ◽  
Vol 83 (10) ◽  
pp. 5077-5086 ◽  
Author(s):  
Lan Wu ◽  
Tongqing Zhou ◽  
Zhi-yong Yang ◽  
Krisha Svehla ◽  
Sijy O'Dell ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Binding Site ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Neutralizing Antibodies ◽  
Outer Domain ◽  
Immunodeficiency Virus ◽  
Cd4 Binding Site ◽  
Hiv 1

ABSTRACT The broadly neutralizing antibody immunoglobulin G1 (IgG1) b12 binds to a conformationally conserved surface on the outer domain of the human immunodeficiency virus type 1 (HIV-1) gp120 envelope (Env) glycoprotein. To develop outer domain proteins (ODs) that could be recognized selectively by CD4-binding-site (CD4-BS) antibodies, membrane-anchored ODs were generated from an HIV-1 clade B virus, TA1 R3A, which was highly sensitive to neutralization by the IgG1 b12 antibody. A 231-residue fragment of gp120 (residues 252 to 482) linked to transmembrane regions from CD4 showed b12 binding comparable to that of the native Env spike as measured by flow cytometry. Truncation of the β20-β21 hairpin (residues 422 to 436 to Gly-Gly) improved overall protein expression. Replacement of the immunodominant central 20 amino acids of the V3 loop (residues 302 to 323) with a basic hexapeptide (NTRGRR) increased b12 reactivity further. Surface calculations indicated that the ratio of b12 epitope to exposed immunogenic surface in the optimized OD increased to over 30%. This OD variant [OD(GSL)(Δβ20-21)(hCD4-TM)] was recognized by b12 and another CD4-BS-reactive antibody, b13, but not by eight other CD4-BS antibodies with limited neutralization potency. Furthermore, optimized membrane-anchored OD selectively absorbed neutralizing activity from complex antisera and b12. Structurally designed membrane-anchored ODs represent candidate immunogens to elicit or to allow the detection of broadly neutralizing antibodies to the conserved site of CD4 binding on HIV-1 gp120.

scholarly journals Neutralizing Antibody Responses in Acute Human Immunodeficiency Virus Type 1 Subtype C Infection

2007 ◽  
Vol 81 (12) ◽  
pp. 6187-6196 ◽  
Author(s):  
E. S. Gray ◽  
P. L. Moore ◽  
I. A. Choge ◽  
J. M. Decker ◽  
F. Bibollet-Ruche ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Neutralizing Antibodies ◽  
Neutralizing Antibody ◽  
Antibody Responses ◽  
Subtype C ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT The study of the evolution and specificities of neutralizing antibodies during the course of human immunodeficiency virus type 1 (HIV-1) infection may be important in the discovery of possible targets for vaccine design. In this study, we assessed the autologous and heterologous neutralization responses of 14 HIV-1 subtype C-infected individuals, using envelope clones obtained within the first 2 months postinfection. Our data show that potent but relatively strain-specific neutralizing antibodies develop within 3 to 12 months of HIV-1 infection. The magnitude of this response was associated with shorter V1-to-V5 envelope lengths and fewer glycosylation sites, particularly in the V1-V2 region. Anti-MPER antibodies were detected in 4 of 14 individuals within a year of infection, while antibodies to CD4-induced (CD4i) epitopes developed to high titers in 12 participants, in most cases before the development of autologous neutralizing antibodies. However, neither anti-MPER nor anti-CD4i antibody specificity conferred neutralization breadth. These data provide insights into the kinetics, potency, breadth, and epitope specificity of neutralizing antibody responses in acute HIV-1 subtype C infection.

scholarly journals Removal of a Single N-Linked Glycan in Human Immunodeficiency Virus Type 1 gp120 Results in an Enhanced Ability To Induce Neutralizing Antibody Responses

2007 ◽  
Vol 82 (2) ◽  
pp. 638-651 ◽  
Author(s):  
Yun Li ◽  
Bradley Cleveland ◽  
Igor Klots ◽  
Bruce Travis ◽  
Barbra A. Richardson ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Neutralizing Antibodies ◽  
Neutralizing Antibody ◽  
Pronounced Increase ◽  
Enhanced Sensitivity ◽  
Subtype B ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Glycans on human immunodeficiency virus (HIV) envelope protein play an important role in infection and evasion from host immune responses. To examine the role of specific glycans, we introduced single or multiple mutations into potential N-linked glycosylation sites in hypervariable regions (V1 to V3) of the env gene of HIV type 1 (HIV-1) 89.6. Three mutants tested showed enhanced sensitivity to soluble CD4. Mutant N7 (N197Q) in the carboxy-terminal stem of the V2 loop showed the most pronounced increase in sensitivity to broadly neutralizing antibodies (NtAbs), including those targeting the CD4-binding site (IgG1b12) and the V3 loop (447-52D). This mutant is also sensitive to CD4-induced NtAb 17b in the absence of CD4. Unlike the wild-type (WT) Env, mutant N7 mediates CD4-independent infection in U87-CXCR4 cells. To study the immunogenicity of mutant Env, we immunized pig-tailed macaques with recombinant vaccinia viruses, one expressing SIVmac239 Gag-Pol and the other expressing HIV-1 89.6 Env gp160 in WT or mutant forms. Animals were boosted 14 to 16 months later with simian immunodeficiency virus gag DNA and the cognate gp140 protein before intrarectal challenge with SHIV89.6P-MN. Day-of-challenge sera from animals immunized with mutant N7 Env had significantly higher and broader neutralizing activities than sera from WT Env-immunized animals. Neutralizing activity was observed against SHIV89.6, SHIV89.6P-MN, HIV-1 SF162, and a panel of subtype B primary isolates. Compared to control animals, immunized animals showed significant reduction of plasma viral load and increased survival after challenge, which correlated with prechallenge NtAb titers. These results indicate the potential advantages for glycan modification in vaccine design, although the role of specific glycans requires further examination.

scholarly journals Nanoparticle Vaccines for Inducing HIV-1 Neutralizing Antibodies

Vaccines ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 76 ◽  
Author(s):  
Mitch Brinkkemper ◽  
Kwinten Sliepen
Keyword(s):  
Envelope Glycoprotein ◽  
Neutralizing Antibodies ◽  
Critical Role ◽  
Neutralizing Antibody ◽  
Antibody Responses ◽  
Broadly Neutralizing Antibodies ◽  
Viral Membrane ◽  
Immunodeficiency Virus ◽  
Hiv 1

The enormous sequence diversity between human immunodeficiency virus type 1 (HIV-1) strains poses a major roadblock for generating a broadly protective vaccine. Many experimental HIV-1 vaccine efforts are therefore aimed at eliciting broadly neutralizing antibodies (bNAbs) that are capable of neutralizing the majority of circulating HIV-1 strains. The envelope glycoprotein (Env) trimer on the viral membrane is the sole target of bNAbs and the key component of vaccination approaches aimed at eliciting bNAbs. Multimeric presentation of Env on nanoparticles often plays a critical role in these strategies. Here, we will discuss the different aspects of nanoparticles in Env vaccination, including recent insights in immunological processes underlying their perceived advantages, the different nanoparticle platforms and the various immunogenicity studies that employed nanoparticles to improve (neutralizing) antibody responses against Env.

Cross -Reactivity of the V3-Specific Antibodies with the Human C1q

2001 ◽  
Vol 56 (11-12) ◽  
pp. 1135-1143 ◽  
Author(s):  
Marijana Petković ◽  
Radmila Metlaš
Keyword(s):  
Lupus Erythematosus ◽  
Sequence Similarity ◽  
Hypervariable Region ◽  
Cross Reactivity ◽  
Specific Antibodies ◽  
Immunodeficiency Virus ◽  
Human Collagen ◽  
Hiv 1 ◽  
Autoimmune Phenomena

Abstract It has been previously shown that the sequence similarity between a portion of the enve­lope glycoprotein 120 (gp120) from the human immunodeficiency virus type-1 (HIV-1) and several types of human collagen and collagen-like molecules exists. That observation led to the suggestion that the antibodies against the third hypervariable region (V3) of HIV-1 gpl20 (V3-specific antibodies) might have a role in the autoimmune phenomena observed in HIV-infected persons. In this study we have examined the cross-reactivity of the V3-specific anti­ bodies purified from sera of HIV-infected individuals, sera obtained from the rheumatoid arthritis and systemic lupus erythematosus patients, as well as from the sera of healthy volun­ teers with the separate chains of a subcomponent of the first component of the human com­ plement system, C1q. Our results show that the V3-specific antibodies are present in the sera of the HIV-infected individuals, patients suffering of the systemic autoimmune diseases as well as in the sera of healthy volunteers. Whereas these antibodies appeared in the HIV+-sera after antigen challenge, those present in the H IV --sera probably represent the antibod­ ies that are cross-reactive with the antigen. V3-reactive antibodies can be purified by affinity chromatography and they were highly specific for the V3-peptide. Additionally, they showed cross-reactivity with the separate chains of the human C1q as well as with the chicken colla­ gen type VI. Possible physiological implications are discussed.

scholarly journals Induction of Primary Virus-Cross-Reactive Human Immunodeficiency Virus Type 1-Neutralizing Antibodies in Small Animals by Using an Alphavirus-Derived In Vivo Expression System

2003 ◽  
Vol 77 (5) ◽  
pp. 3119-3130 ◽  
Author(s):  
Ming Dong ◽  
Peng Fei Zhang ◽  
Franziska Grieder ◽  
James Lee ◽  
Govindaraj Krishnamurthy ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Neutralizing Antibodies ◽  
Neutralizing Activity ◽  
Immunodeficiency Virus ◽  
Hiv 1 ◽  
Primary Virus

ABSTRACT We have studied the induction of neutralizing antibodies by in vivo expression of the human immunodeficiency virus type 1 (HIV-1) envelope by using a Venezuelan equine encephalitis virus (VEE) replicon system with mice and rabbits. The HIV-1 envelope, clone R2, has broad sensitivity to cross-reactive neutralization and was obtained from a donor with broadly cross-reactive, primary virus-neutralizing antibodies (donor of reference serum, HIV-1-neutralizing serum 2 [HNS2]). It was expressed as gp160, as secreted gp140, and as gp160ΔCT with the cytoplasmic tail deleted. gp140 was expressed in vitro at a high level and was predominantly uncleaved oligomer. gp160ΔCT was released by cells in the form of membrane-bound vesicles. gp160ΔCT induced stronger neutralizing responses than the other forms. Use of a helper plasmid for replicon particle packaging, in which the VEE envelope gene comprised a wild-type rather than a host range-adapted sequence, also enhanced immunogenicity. Neutralizing activity fractionated with immunoglobulin G. This activity was cross-reactive among a panel of five nonhomologous primary clade B strains and a Chinese clade C strain and minimally reactive against a Chinese clade E (circulating recombinant form 1) strain. The comparative neutralization of these strains by immune mouse sera was similar to the relative neutralizing effects of HNS2, and responses induced in rabbits were similar to those induced in mice. Together, these results demonstrate that neutralizing antibody responses can be induced in mice within 2 to 3 months that are similar in potency and cross-reactivity to those found in the chronically infected, long-term nonprogressive donor of HNS2. These findings support the expectation that induction of highly cross-reactive HIV-1 primary virus-neutralizing activity by vaccination may be realized.

Sign in / Sign up

Export Citation Format

Share Document