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 Human Immunodeficiency Virus Type 1 Superinfection Occurs despite Relatively Robust Neutralizing Antibody Responses

2008 ◽  
Vol 82 (24) ◽  
pp. 12094-12103 ◽  
Author(s):  
Catherine A. Blish ◽  
Ozge C. Dogan ◽  
Nina R. Derby ◽  
Minh-An Nguyen ◽  
Bhavna Chohan ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Neutralizing Antibodies ◽  
Natural Infection ◽  
Neutralizing Antibody ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Superinfection by a second human immunodeficiency virus type 1 (HIV-1) strain indicates that gaps in protective immunity occur during natural infection. To define the role of HIV-1-specific neutralizing antibodies (NAbs) in this setting, we examined NAb responses in 6 women who became superinfected between ∼1 to 5 years following initial infection compared to 18 women with similar risk factors who did not. Although superinfected individuals had less NAb breadth than matched controls at ∼1 year postinfection, no significant differences in the breadth or potency of NAb responses were observed just prior to the second infection. In fact, four of the six subjects had relatively broad and potent NAb responses prior to infection by the second strain. To more specifically examine the specificity of the NAbs against the superinfecting virus, these variants were cloned from five of the six individuals. The superinfecting variants did not appear to be inherently neutralization resistant, as measured against a pool of plasma from unrelated HIV-infected individuals. Moreover, the superinfected individuals were able to mount autologous NAb responses to these variants following reinfection. In addition, most superinfected individuals had NAbs that could neutralize their second viral strains prior to their reinfection, suggesting that the level of NAbs elicited during natural infection was not sufficient to block infection. These data indicate that preventing infection by vaccination will likely require broader and more potent NAb responses than those found in HIV-1-infected individuals.

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 Induction of Neutralizing Antibodies against Human Immunodeficiency Virus Type 1 Primary Isolates by Gag-Env Pseudovirion Immunization

2005 ◽  
Vol 79 (23) ◽  
pp. 14804-14814 ◽  
Author(s):  
Jason Hammonds ◽  
Xuemin Chen ◽  
Timothy Fouts ◽  
Anthony DeVico ◽  
David Montefiori ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Neutralizing Antibodies ◽  
Neutralizing Antibody ◽  
Antibody Responses ◽  
Oil Emulsion ◽  
Cpg Oligodeoxynucleotides ◽  
Immunodeficiency Virus ◽  
Monomeric Gp120

ABSTRACT A major challenge for the development of an effective HIV vaccine is to elicit neutralizing antibodies against a broad array of primary isolates. Monomeric gp120-based vaccine approaches have not been successful in inducing this type of response, prompting a number of approaches designed to recreate the native glycoprotein complex that exists on the viral membrane. Gag-Env pseudovirions are noninfectious viruslike particles that recreate the native envelope glycoprotein structure and have the potential to generate neutralizing antibody responses against primary isolates. In this study, an inducible cell line was created in order to generate Gag-Env pseudovirions for examination of neutralizing antibody responses in guinea pigs. Unadjuvanted pseudovirions generated relatively weak anti-gp120 responses, while the use of a block copolymer water-in-oil emulsion or aluminum hydroxide combined with CpG oligodeoxynucleotides resulted in high levels of antibodies that bind to gp120. Sera from immunized animals neutralized a panel of human immunodeficiency virus (HIV) type 1 primary isolate viruses at titers that were significantly higher than that of the corresponding monomeric gp120 protein. Interpretation of these results was complicated by the occurrence of neutralizing antibodies directed against cellular (non-envelope protein) components of the pseudovirion. However, a major component of the pseudovirion-elicited antibody response was directed specifically against the HIV envelope. These results provide support for the role of pseudovirion-based vaccines in generating neutralizing antibodies against primary isolates of HIV and highlight the potential confounding role of antibodies directed at non-envelope cell surface components.

scholarly journals Breadth of Neutralizing Antibody Response to Human Immunodeficiency Virus Type 1 Is Affected by Factors Early in Infection but Does Not Influence Disease Progression

2009 ◽  
Vol 83 (19) ◽  
pp. 10269-10274 ◽  
Author(s):  
Anne Piantadosi ◽  
Dana Panteleeff ◽  
Catherine A. Blish ◽  
Jared M. Baeten ◽  
Walter Jaoko ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Viral Load ◽  
Disease Progression ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Neutralizing Antibody ◽  
Subtype B ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT The determinants of a broad neutralizing antibody (NAb) response and its effect on human immunodeficiency virus type 1 (HIV-1) disease progression are not well defined, partly because most prior studies of a broad NAb response were cross-sectional. We examined correlates of NAb response breadth among 70 HIV-infected, antiretroviral-naïve Kenyan women from a longitudinal seroincident cohort. NAb response breadth was measured 5 years after infection against five subtype A viruses and one subtype B virus. Greater NAb response breadth was associated with a higher viral load set point and greater HIV-1 env diversity early in infection. However, greater NAb response breadth was not associated with a delayed time to a CD4+ T-cell count of <200, antiretroviral therapy, or death. Thus, a broad NAb response results from a high level of antigenic stimulation early in infection, which likely accounts for prior observations that greater NAb response breadth is associated with a higher viral load later in infection.

scholarly journals Viral Phenotypes and Antibody Responses in Long-Term Survivors Infected with Attenuated Human Immunodeficiency Virus Type 1 Containing Deletions in the nef and Long Terminal Repeat Regions

2007 ◽  
Vol 81 (17) ◽  
pp. 9268-9278 ◽  
Author(s):  
Erin E. Verity ◽  
Dimitra Zotos ◽  
Kim Wilson ◽  
Catherine Chatfield ◽  
Victoria A. Lawson ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Neutralizing Antibodies ◽  
Neutralizing Antibody ◽  
Antibody Responses ◽  
Wild Type Virus ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT The Sydney Blood Bank Cohort (SBBC) consists of eight blood transfusion recipients infected with nef-attenuated human immunodeficiency virus type 1 (HIV-1) acquired from a single donor. Here, we show that viral phenotypes and antibody responses differ considerably between individual cohort members, despite the single source of infection. Replication of isolated virus varied from barely detectable to similar to that of the wild-type virus, and virus isolated from five SBBC members showed coreceptor usage signatures unique to each individual. Higher viral loads and stronger neutralizing antibody responses were associated with better-replicating viral strains, and detectable viral replication was essential for the development of strong and sustained humoral immune responses. Despite the presence of strong neutralizing antibodies in a number of SBBC members, disease progression was not prevented, and each cohort member studied displayed a unique outcome of infection with nef-attenuated HIV-1.

scholarly journals Profiling the Specificity of Neutralizing Antibodies in a Large Panel of Plasmas from Patients Chronically Infected with Human Immunodeficiency Virus Type 1 Subtypes B and C

2008 ◽  
Vol 82 (23) ◽  
pp. 11651-11668 ◽  
Author(s):  
James M. Binley ◽  
Elizabeth A. Lybarger ◽  
Emma T. Crooks ◽  
Michael S. Seaman ◽  
Elin Gray ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Neutralizing Antibodies ◽  
Significant Proportion ◽  
Neutralizing Activity ◽  
Subtype B ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Identifying the viral epitopes targeted by broad neutralizing antibodies (NAbs) that sometimes develop in human immunodeficiency virus type 1 (HIV-1)-infected subjects should assist in the design of vaccines to elicit similar responses. Here, we investigated the activities of a panel of 24 broadly neutralizing plasmas from subtype B- and C-infected donors using a series of complementary mapping methods, focusing mostly on JR-FL as a prototype subtype B primary isolate. Adsorption with gp120 immobilized on beads revealed that an often large but variable fraction of plasma neutralization was directed to gp120 and that in some cases, neutralization was largely mediated by CD4 binding site (CD4bs) Abs. The results of a native polyacrylamide gel electrophoresis assay using JR-FL trimers further suggested that half of the subtype B and a smaller fraction of subtype C plasmas contained a significant proportion of NAbs directed to the CD4bs. Anti-gp41 neutralizing activity was detected in several plasmas of both subtypes, but in all but one case, constituted only a minor fraction of the overall neutralization activity. Assessment of the activities of the subtype B plasmas against chimeric HIV-2 viruses bearing various fragments of the membrane proximal external region (MPER) of HIV-1 gp41 revealed mixed patterns, implying that MPER neutralization was not dominated by any single specificity akin to known MPER-specific monoclonal Abs. V3 and 2G12-like NAbs appeared to make little or no contribution to JR-FL neutralization titers. Overall, we observed significant titers of anti-CD4bs NAbs in several plasmas, but approximately two-thirds of the neutralizing activity remained undefined, suggesting the existence of NAbs with specificities unlike any characterized to date.

scholarly journals Human Immunodeficiency Virus Type 1 Escape from Cyclotriazadisulfonamide-Induced CD4-Targeted Entry Inhibition Is Associated with Increased Neutralizing Antibody Susceptibility

2009 ◽  
Vol 83 (18) ◽  
pp. 9577-9583 ◽  
Author(s):  
Kurt Vermeire ◽  
Kristel Van Laethem ◽  
Wouter Janssens ◽  
Thomas W. Bell ◽  
Dominique Schols
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Neutralizing Antibodies ◽  
Neutralizing Antibody ◽  
Receptor Expression ◽  
Antibody Treatment ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Continuous specific downmodulation of CD4 receptor expression in T lymphocytes by the small molecule cyclotriazadisulfonamide (CADA) selected for the CADA-resistant human immunodeficiency virus type 1 (HIV-1) NL4.3 virus containing unique mutations in the C4 and V5 regions of gp120, likely stabilizing the CD4-binding conformation. The amino acid changes in Env were associated with decreased susceptibility to anti-CD4 monoclonal antibody treatment of the cells and with higher susceptibility of the virus to soluble CD4. In addition, the acquired ability of a CADA-resistant virus to infect cells with low CD4 expression was associated with an increased susceptibility of the virus to neutralizing antibodies from sera of several HIV-1-infected patients.

scholarly journals Cross-Subtype Neutralizing Antibodies Induced in Baboons by a Subtype E gp120 Immunogen Based on an R5 Primary Human Immunodeficiency Virus Type 1 Envelope

1999 ◽  
Vol 73 (6) ◽  
pp. 4640-4650 ◽  
Author(s):  
Thomas C. VanCott ◽  
John R. Mascola ◽  
Lawrence D. Loomis-Price ◽  
Faruk Sinangil ◽  
Naamah Zitomersky ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Neutralizing Antibodies ◽  
Intravenous Drug User ◽  
Subtype B ◽  
Neutralizing Capacity ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Global human immunodeficiency virus type 1 (HIV-1) diversity may require engineering vaccines to express antigens representing strains prevalent in the target population of vaccine testing. The majority (90%) of incident infections in Thailand are genetic subtype E, with a small percentage of subtype B infections in the intravenous drug user populations. We have evaluated and compared the binding and HIV-1 neutralizing properties of serum antibodies induced in baboons by CHO cell-expressed monomeric gp120 derived from a CCR5-using (R5) subtype E primary HIV-1CM235 or a CXCR4-using (X4) subtype B T-cell line-adapted (TCLA) HIV-1SF2 isolate. In contrast to the subtype-specific HIV-1 neutralizing antibodies induced with recombinant HIV-1SF2 gp120 (rgp120SF2), rgp120CM235 immunization induced antibodies capable of neutralizing both subtype E and subtype B TCLA HIV-1 isolates. However, neither immunogen induced antibodies capable of neutralizing primary HIV-1 isolates. Antibody induced by rgp120CM235 preferentially bound natively folded gp120 and retained strong cross-reactivity against multiple gp120 strains within subtype E as well as subtype B. In contrast, antibody responses to rgp120SF2 were directed predominantly to linear epitopes poorly exposed on native gp120 and had more limited cross-recognition of divergent gp120. Fine epitope mapping revealed differences in antibody specificities. While both rgp120CM235 and rgp120SF2 induced antibodies to regions within C1, V1/V2, V3, and C5, unique responses were induced by rgp120CM235 to multiple epitopes within C2 and by rgp120SF2 to multiple epitopes within C3, V4, and C4. These data demonstrate that strain and/or phenotypic differences of HIV-1 subunit gp120 immunogens can substantially alter antibody binding specificities and subsequent HIV-1 neutralizing capacity.

scholarly journals A Variable Region 3 (V3) Mutation Determines a Global Neutralization Phenotype and CD4-Independent Infectivity of a Human Immunodeficiency Virus Type 1 Envelope Associated with a Broadly Cross-Reactive, Primary Virus-Neutralizing Antibody Response

2002 ◽  
Vol 76 (2) ◽  
pp. 644-655 ◽  
Author(s):  
Peng Fei Zhang ◽  
Peter Bouma ◽  
Eun Ju Park ◽  
Joseph B. Margolick ◽  
James E. Robinson ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Variable Region ◽  
Neutralizing Antibody ◽  
Cross Reactivity ◽  
Enhanced Sensitivity ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT The human serum human immunodeficiency virus type 1 (HIV-1)-neutralizing serum 2 (HNS2) neutralizes many primary isolates of different clades of HIV-1, and virus expressing envelope from the same donor, clone R2, is neutralized cross-reactively by HIV-immune human sera. The basis for this cross-reactivity was investigated. It was found that a rare mutation in the proximal limb of variable region 3 (V3), 313-4 PM, caused virus pseudotyped with the R2 envelope to be highly sensitive to neutralization by monoclonal antibodies (MAbs) directed against conformation-sensitive epitopes at the tip of the V3 loop, such as 19b, and moderately sensitive to MAbs against CD4 binding site (CD4bs) and CD4-induced (CD4i) epitopes, soluble CD4 (sCD4), and HNS2. In addition, introduction of this sequence by mutagenesis caused enhanced sensitivity to neutralization by 19b, anti-CD4i MAb, and HNS2 in three other primary HIV-1 envelopes and by anti-CD4bs MAb and sCD4 in one of the three. The 313-4 PM sequence also conferred increased infectivity for CD4+ CCR5+ cells and the ability to infect CCR5+ cells upon all of these four and two of these four HIV-1 envelopes, respectively. Neutralization of R2 by HNS2 was substantially inhibited by the cyclized R2 V3 35-mer synthetic peptide. Similarly, the peptide also had some lesser efficacy in blocking neutralization of R2 by other sera or of neutralization of other primary viruses by HNS2. Together, these results indicate that the unusual V3 mutation in the R2 clone accounts for its uncommon neutralization sensitivity phenotype and its capacity to mediate CD4-independent infection, both of which could relate to immunogenicity and the neutralizing activity of HNS2. This is also the first primary HIV-1 isolate envelope glycoprotein found to be competent for CD4-independent infection.

scholarly journals Human Immunodeficiency Virus Type 1 env Clones from Acute and Early Subtype B Infections for Standardized Assessments of Vaccine-Elicited Neutralizing Antibodies

2005 ◽  
Vol 79 (16) ◽  
pp. 10108-10125 ◽  
Author(s):  
Ming Li ◽  
Feng Gao ◽  
John R. Mascola ◽  
Leonidas Stamatatos ◽  
Victoria R. Polonis ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
Standardized Assessments ◽  
Subtype B ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Induction of broadly cross-reactive neutralizing antibodies is a high priority for AIDS vaccine development but one that has proven difficult to be achieved. While most immunogens generate antibodies that neutralize a subset of T-cell-line-adapted strains of human immunodeficiency virus type 1 (HIV-1), none so far have generated a potent, broadly cross-reactive response against primary isolates of the virus. Even small increments in immunogen improvement leading to increases in neutralizing antibody titers and cross-neutralizing activity would accelerate vaccine development; however, a lack of uniformity in target strains used by different investigators to assess cross-neutralization has made the comparison of vaccine-induced antibody responses difficult. Thus, there is an urgent need to establish standard panels of HIV-1 reference strains for wide distribution. To facilitate this, full-length gp160 genes were cloned from acute and early subtype B infections and characterized for use as reference reagents to assess neutralizing antibodies against clade B HIV-1. Individual gp160 clones were screened for infectivity as Env-pseudotyped viruses in a luciferase reporter gene assay in JC53-BL (TZM-bl) cells. Functional env clones were sequenced and their neutralization phenotypes characterized by using soluble CD4, monoclonal antibodies, and serum samples from infected individuals and noninfected recipients of a recombinant gp120 vaccine. Env clones from 12 R5 primary HIV-1 isolates were selected that were not unusually sensitive or resistant to neutralization and comprised a wide spectrum of genetic, antigenic, and geographic diversity. These reference reagents will facilitate proficiency testing and other validation efforts aimed at improving assay performance across laboratories and can be used for standardized assessments of vaccine-elicited neutralizing antibodies.

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