Article

Human Immunodeficiency Virus Type 1 Env Trimer Immunization of Macaques and Impact of Priming with Viral Vector or Stabilized Core Protein

Swedish Institute for Infectious Disease Control, Solna, Sweden.
Journal of Virology (Impact Factor: 4.65). 12/2008; 83(2):540-51. DOI: 10.1128/JVI.01102-08
Source: PubMed

ABSTRACT Currently there is limited information about the quality of immune responses elicited by candidate human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein (Env)-based immunogens in primates. Here we describe a comprehensive analysis of neutralizing antibody and T-cell responses obtained in cynomolgus macaques by three selected immunization regimens. We used the previously described YU2-based gp140 protein trimers administered in an adjuvant, preceded by two distinct priming strategies: either alphavirus replicon particles expressing matched gp140 trimers or gp120 core proteins stabilized in the CD4-bound conformation. The rationale for priming with replicon particles was to evaluate the impact of the expression platform on trimer immunogenicity. The stable core proteins were chosen in an attempt to expand selectively lymphocytes recognizing common determinants between the core and trimers to broaden the immune response. The results presented here demonstrate that the platform by which Env trimers were delivered in the priming (either protein or replicon vector) had little impact on the overall immune response. In contrast, priming with stable core proteins followed by a trimer boost strikingly focused the T-cell response on the core sequences of HIV-1 Env. The specificity of the T-cell response was distinctly different from that of the responses obtained in animals immunized with trimers alone and was shown to be mediated by CD4(+) T cells. However, this regimen showed limited or no improvement in the neutralizing antibody responses, suggesting that further immunogen design efforts are required to successfully focus the B-cell response on conserved neutralizing determinants of HIV-1 Env.

Download full-text

Full-text

Available from: Christopher Sundling, Aug 31, 2015
0 Followers
 · 
199 Views
  • Source
    • "The basis for the augmented NtAb responses induced by deglycosylated Env mutants remains to be further investigated. Nevertheless, our observations add important information to the approach aiming to induce neutralizing antibodies that recognize the functional trimeric Env complex (Dey et al., 2007; Fouts et al., 2002; Morner et al., 2009; Pantophlet and Burton, 2006). Given the relative poor immunogenicity of HIV-1 Env DNA (Robinson, 2009), while beyond the scope of this study, it will be important to determine whether a heterologous DNA prime followed by boosting with matched deglycosylated Env protein could increase the observed immune activity reported here. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Glycosylation plays important roles in gp120 structure and HIV-1 immune evasion. In the current study, we introduced deglycosylations into the 24 N-linked glycosylation sites of a R5 env MWS2 cloned from semen and systematically analyzed the impact on infectivity, antigenicity, immunogenicity and sensitivity to entry inhibitors. We found that mutants N156-T158A, N197-S199A, N262-S264A and N410-T412A conferred decreased infectivity and enhanced sensitivity to a series of antibodies and entry inhibitors. When mice were immunized with the DNA of wild-type or mutated gp160, gp140 or gp120; N156-T158A, N262-S264A and N410-T412A were more effective in inducing neutralizing activity against wild-type MWS2 as well as heterologous IIIB and CH811 Envs. In general, gp160 and gp140 induced higher neutralizing activity compared with gp120. Our study demonstrates for the first time that removal of individual glycan N156, N262 or N410 proximal to CD4-binding region impairs viral infectivity and results in enhanced capability to induce neutralizing activity.
    Virology 12/2011; 423(1):97-106. DOI:10.1016/j.virol.2011.11.023 · 3.28 Impact Factor
  • Source
    • "The basis for the augmented NtAb responses induced by deglycosylated Env mutants remains to be further investigated. Nevertheless, our observations add important information to the approach aiming to induce neutralizing antibodies that recognize the functional trimeric Env complex (Dey et al., 2007; Fouts et al., 2002; Morner et al., 2009; Pantophlet and Burton, 2006). Given the relative poor immunogenicity of HIV-1 Env DNA (Robinson, 2009), while beyond the scope of this study, it will be important to determine whether a heterologous DNA prime followed by boosting with matched deglycosylated Env protein could increase the observed immune activity reported here. "
    [Show abstract] [Hide abstract]
    ABSTRACT: High-mannose N-linked glycans recognized by carbohydrate-binding agents (CBAs) are potential targets for topical microbicides. To better understand the mechanisms by which CBAs inhibit human immunodeficiency virus (HIV)-1 infection at the molecular level, we systematically analysed the contribution of site-specific glycans to the anti-HIV activity of CBAs by site-directed mutagenesis. Our results demonstrate that a single deglycosylation at N295 or N448 in a range of primary and T-cell-line-adapted HIV-1 isolates resulted in marked resistance to griffithsin (GRFT) but maintained the sensitivity to cyanovirin (CV-N), Galanthus nivalis agglutinin (GNA) and a range of neutralizing antibodies. Unlike CV-N and GNA, the interaction between GRFT and gp120 appeared to be dependent on the specific trimeric 'sugar tower' including N295 and N448. This was further strengthened by the results of GRFT-Env binding experiments. Our study identifies GRFT-specific gp120 glycans and may provide information for the design of novel CBA antiviral strategies.
    Journal of General Virology 06/2011; 92(Pt 10):2367-73. DOI:10.1099/vir.0.033092-0 · 3.53 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Studies were performed to induce cross-clade neutralizing antibodies (Abs) by testing various combinations of prime and boost constructs that focus the immune response on structurally-conserved epitopes in the V3 loop of HIV-1 gp120. Rabbits were immunized with gp120 DNA containing a V3 loop characterized by the GPGR motif at its tip, and/or with gp120 DNA with a V3 loop carrying the GPGQ motif. Priming was followed by boosts with V3-fusion proteins (V3-FPs) carrying the V3 sequence from a subtype B virus (GPGR motif), and/or with V3 sequences from subtypes A and C (GPGQ motif). The broadest and most consistent neutralizing responses were generated when using a clade C gp120 DNA prime and with the V3(B)-FP boost. Immune sera displayed neutralizing activity in three assays against pseudoviruses and primary isolates from subtypes A, AG, B, C, and D. Polyclonal Abs in the immune rabbit sera neutralized viruses that were not neutralized by pools of human anti-V3 monoclonal Abs. Greater than 80% of the neutralizing Abs were specific for V3, showing that the immune response could be focused on a neutralizing epitope and that vaccine-induced anti-V3 Abs have cross-clade neutralizing activity.
    Virology 08/2009; 392(1):82-93. DOI:10.1016/j.virol.2009.05.039 · 3.28 Impact Factor
Show more