A multiclade env–gag VLP mRNA vaccine elicits tier-2 HIV-1-neutralizing antibodies and reduces the risk of heterologous SHIV infection in macaques

Stabilized HIV-1 envelope (Env) trimers elicit tier 2 autologous neutralizing antibody (nAb) responses in immunized animals. We previously demonstrated that BG505 SOSIP.664.T332N gp140 (BG505 SOSIP) immunization of rhesus macaques (RM) provided robust protection against autologous intra-vaginal simian-human immunodeficiency virus (SHIV) challenge that was predicted by high serum nAb titers. Here, we show that nAb in these protected RM targeted a glycan hole proximal to residue 465 in gp120 in all cases. nAb also targeted another glycan hole at residues 241/289 and an epitope in V1 at varying frequencies. Non-neutralizing antibodies directed at N611-shielded epitopes in gp41 were also present but were more prevalent in RM with low nAb titers. Longitudinal analysis demonstrated that nAb broadened in some RM during sequential immunization but remained focused in others, the latter being associated with increases in nAb titer. Thirty-eight monoclonal antibodies (mAbs) isolated from a protected RM with an exceptionally high serum neutralization titer bound to the trimer in ELISA, and four of the mAbs potently neutralized the BG505 Env pseudovirus (PV) and SHIV. The four neutralizing mAbs were clonally related and targeted the 465 glycan hole to varying degrees, mimicking the serum. The data demonstrate that the C3/465 glycan hole cluster was the dominant neutralization target in high titer protected RM, despite other co-circulating neutralizing and non-neutralizing specificities. The isolation of a neutralizing mAb family argues that clonotype expansion occurred during BG505 SOSIP immunization, leading to high titer, protective nAb and setting a desirable benchmark for HIV vaccines.

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A Prime-Boost Immunization Strategy with Vaccinia Virus Expressing Novel gp120 Envelope Glycoprotein from a CRF02_AG Isolate Elicits Cross-Clade Tier 2 HIV-1 Neutralizing Antibodies

Vaccines ◽

10.3390/vaccines8020171 ◽

2020 ◽

Vol 8 (2) ◽

pp. 171

Author(s):

Rita Calado ◽

Joana Duarte ◽

Pedro Borrego ◽

José Maria Marcelino ◽

Inês Bártolo ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Envelope Glycoproteins ◽

The Novel ◽

Tier 2 ◽

Broadly Neutralizing Antibodies ◽

Immunization Strategy ◽

Vaccinia Viruses ◽

Boost Immunization ◽

Almost All ◽

Hiv 1

Development of new immunogens eliciting broadly neutralizing antibodies (bNAbs) is a main priority for the HIV-1 vaccine field. Envelope glycoproteins from non-B-non-C HIV-1clades have not been fully explored as components of a vaccine. We produced Vaccinia viruses expressing a truncated version of gp120 (gp120t) from HIV-1 clades CRF02_AG, H, J, B, and C and examined their immunogenicity in mice and rabbits. Mice primed with the recombinant Vaccinia viruses and boosted with the homologous gp120t or C2V3C3 polypeptides developed antibodies that bind potently to homologous and heterologous envelope glycoproteins. Notably, a subset of mice immunized with the CRF02_AG-based envelope immunogens developed a cross-reactive neutralizing response against tier 2 HIV-1 Env-pseudoviruses and primary isolates. Rabbits vaccinated with the CRF02_AG-based envelope immunogens also generated potent binding antibodies, and one animal elicited antibodies that neutralized almost all (13 of 16, 81.3%) tier 2 HIV-1 isolates tested. Overall, the results suggest that the novel CRF02_AG-based envelope immunogens and prime-boost immunization strategy elicit the type of immune responses required for a preventive HIV-1 vaccine.

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Enhanced HIV-1 immunotherapy by commonly arising antibodies that target virus escape variants

Journal of Experimental Medicine ◽

10.1084/jem.20141050 ◽

2014 ◽

Vol 211 (12) ◽

pp. 2361-2372 ◽

Cited By ~ 57

Author(s):

Florian Klein ◽

Lilian Nogueira ◽

Yoshiaki Nishimura ◽

Ganesh Phad ◽

Anthony P. West ◽

...

Keyword(s):

Human Immunodeficiency Virus ◽

Neutralizing Antibodies ◽

Viral Escape ◽

Humanized Mice ◽

Broadly Neutralizing Antibodies ◽

Virus Escape ◽

Immunodeficiency Virus ◽

Shiv Infection ◽

Hiv 1

Antibody-mediated immunotherapy is effective in humanized mice when combinations of broadly neutralizing antibodies (bNAbs) are used that target nonoverlapping sites on the human immunodeficiency virus type 1 (HIV-1) envelope. In contrast, single bNAbs can control simian–human immunodeficiency virus (SHIV) infection in immune-competent macaques, suggesting that the host immune response might also contribute to the control of viremia. Here, we investigate how the autologous antibody response in intact hosts can contribute to the success of immunotherapy. We find that frequently arising antibodies that normally fail to control HIV-1 infection can synergize with passively administered bNAbs by preventing the emergence of bNAb viral escape variants.

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DNA Vaccine Molecular Adjuvants SP-D-BAFF and SP-D-APRIL Enhance Anti-gp120 Immune Response and Increase HIV-1 Neutralizing Antibody Titers

Journal of Virology ◽

10.1128/jvi.02904-14 ◽

2015 ◽

Vol 89 (8) ◽

pp. 4158-4169 ◽

Cited By ~ 22

Author(s):

Sachin Gupta ◽

Emily S. Clark ◽

James M. Termini ◽

Justin Boucher ◽

Saravana Kanagavelu ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Surfactant Protein ◽

Surfactant Protein D ◽

Tier 2 ◽

Tier 1 ◽

Membrane Bound ◽

Molecular Adjuvants ◽

Anti Hiv ◽

Hiv 1 ◽

Antibody Secreting Cells

ABSTRACTBroadly neutralizing antibodies (bNAbs) specific for conserved epitopes on the HIV-1 envelope (Env) are believed to be essential for protection against multiple HIV-1 clades. However, vaccines capable of stimulating the production of bNAbs remain a major challenge. Given that polyreactivity and autoreactivity are considered important characteristics of anti-HIV bNAbs, we designed an HIV vaccine incorporating the molecular adjuvants BAFF (B cell activating factor) and APRIL (a proliferation-inducing ligand) with the potential to facilitate the maturation of polyreactive and autoreactive B cells as well as to enhance the affinity and/or avidity of Env-specific antibodies. We designed recombinant DNA plasmids encoding soluble multitrimers of BAFF and APRIL using surfactant protein D as a scaffold, and we vaccinated mice with these molecular adjuvants using DNA and DNA-protein vaccination strategies. We found that immunization of mice with a DNA vaccine encoding BAFF or APRIL multitrimers, together with interleukin 12 (IL-12) and membrane-bound HIV-1 Env gp140, induced neutralizing antibodies against tier 1 and tier 2 (vaccine strain) viruses. The APRIL-containing vaccine was particularly effective at generating tier 2 neutralizing antibodies following a protein boost. These BAFF and APRIL effects coincided with an enhanced germinal center (GC) reaction, increased anti-gp120 antibody-secreting cells, and increased anti-gp120 functional avidity. Notably, BAFF and APRIL did not cause indiscriminate B cell expansion or an increase in total IgG. We propose that BAFF and APRIL multitrimers are promising molecular adjuvants for vaccines designed to induce bNAbs against HIV-1.IMPORTANCERecent identification of antibodies that neutralize most HIV-1 strains has revived hopes and efforts to create novel vaccines that can effectively stimulate HIV-1 neutralizing antibodies. However, the multiple immune evasion properties of HIV have hampered these efforts. These include the instability of the gp120 trimer, the inaccessibility of the conserved sequences, highly variable protein sequences, and the loss of HIV-1-specific antibody-producing cells during development. We have shown previously that tumor necrosis factor (TNF) superfamily ligands, including BAFF and APRIL, can be multitrimerized using the lung protein SP-D (surfactant protein D), enhancing immune responses. Here we show that DNA or DNA-protein vaccines encoding BAFF or APRIL multitrimers, IL-12p70, and membrane-bound HIV-1 Env gp140 induced tier 1 and tier 2 neutralizing antibodies in a mouse model. BAFF and APRIL enhanced the immune reaction, improved antibody binding, and increased the numbers of anti-HIV-1 antibody-secreting cells. Adaptation of this vaccine design may prove useful in designing preventive HIV-1 vaccines for humans.

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Reducing V3 Antigenicity and Immunogenicity on Soluble, Native-Like HIV-1 Env SOSIP Trimers

Journal of Virology ◽

10.1128/jvi.00677-17 ◽

2017 ◽

Vol 91 (15) ◽

Cited By ~ 23

Author(s):

Rajesh P. Ringe ◽

Gabriel Ozorowski ◽

Kimmo Rantalainen ◽

Weston B. Struwe ◽

Katie Matthews ◽

...

Keyword(s):

Animal Models ◽

Neutralizing Antibodies ◽

Vaccine Development ◽

Tier 2 ◽

Present Generation ◽

Coreceptor Binding ◽

Tier 1 ◽

Immunogen Design ◽

V3 Region ◽

Hiv 1

ABSTRACT Native-like trimers of the SOSIP design are being developed as immunogens in human immunodeficiency virus type 1 (HIV-1) vaccine development programs. These trimers display the epitopes for multiple broadly neutralizing antibodies (bNAbs) but can also expose binding sites for some types of nonneutralizing antibodies (non-NAbs). Among the latter are epitopes in the gp120 V3 region that are highly immunogenic when SOSIP trimers are evaluated in animal models. It is presently uncertain whether antibodies against V3 can interfere with the induction of NAbs, but there are good arguments in favor of suppressing such “off-target” immune responses. Accordingly, we have assessed how to minimize the exposure of V3 non-NAb epitopes and thereby reduce their immunogenicity by introducing N-glycans within the V3 region of BG505 SOSIP trimers. We found that inserting glycans at positions 306 and 314 (termed M1 and M7) markedly reduced V3 antigenicity while improving the presentation of trimer apex bNAb epitopes. Both added glycans were shown to be predominantly of the Man6GlcNAc2 form. The additional introduction of the E64K ground-state stabilizing substitution markedly reduced or ablated soluble CD4 (sCD4) induction of non-NAb epitopes in V3 and/or associated with the coreceptor binding site. When a V3 glycan- and E64K-modified trimer variant, BG505 SOSIP.664-E64K.M1M7, was tested in rabbits, V3 immunogenicity was eliminated while the autologous NAb response was unchanged. IMPORTANCE Trimeric proteins are being developed for future HIV-1 vaccine trials in humans, with the goal of eliciting broadly active neutralizing antibodies (NAbs) that are active against a wide variety of circulating strains. In animal models, the present generation of native-like trimer immunogens, exemplified by the BG505 SOSIP.664 construct, induces narrow-specificity antibodies against the neutralization-resistant (tier-2), sequence-matched virus and more broadly active antibodies against sequence-divergent atypically neutralization-sensitive (tier-1) viruses. A concern in the trimer immunogen design field has been whether the latter off-target antibodies might interfere with the induction of the more desired responses to tier-2 epitopes. Here, we have inserted two glycans into the dominant site for tier-1 NAbs, the gp120 V3 region, to block the induction of off-target antibodies. We characterized the new trimers, tested them as immunogens in rabbits, and found that the blocking glycans eliminated the induction of tier-1 NAbs to V3-epitopes.

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Breadth of Neutralizing Antibodies Elicited by Stable, Homogeneous Clade A and Clade C HIV-1 gp140 Envelope Trimers in Guinea Pigs

Journal of Virology ◽

10.1128/jvi.02252-09 ◽

2010 ◽

Vol 84 (7) ◽

pp. 3270-3279 ◽

Cited By ~ 73

Author(s):

Joseph P. Nkolola ◽

Hanqin Peng ◽

Ethan C. Settembre ◽

Michael Freeman ◽

Lauren E. Grandpre ◽

...

Keyword(s):

Guinea Pigs ◽

Neutralizing Antibodies ◽

Recombinant Adenovirus ◽

Neutralizing Antibody ◽

Tier 2 ◽

Antigenic Properties ◽

Tier 1 ◽

Clade C ◽

Gp140 Envelope ◽

Hiv 1

ABSTRACT The native envelope (Env) spike on the surface of human immunodeficiency virus type 1 (HIV-1) is trimeric, and thus trimeric Env vaccine immunogens are currently being explored in preclinical immunogenicity studies. Key challenges have included the production and purification of biochemically homogeneous and stable trimers and the evaluation of these immunogens utilizing standardized virus panels for neutralization assays. Here we report the binding and neutralizing antibody (NAb) responses elicited by clade A (92UG037.8) and clade C (CZA97.012) Env gp140 trimer immunogens in guinea pigs. These trimers have been selected and engineered for optimal biochemical stability and have defined antigenic properties. Purified gp140 trimers with Ribi adjuvant elicited potent, cross-clade NAb responses against tier 1 viruses as well as detectable but low-titer NAb responses against select tier 2 viruses from clades A, B, and C. In particular, the clade C trimer elicited NAbs that neutralized 27%, 20%, and 47% of tier 2 viruses from clades A, B, and C, respectively. Heterologous DNA prime, protein boost as well as DNA prime, recombinant adenovirus boost regimens expressing these antigens, however, did not result in an increased magnitude or breadth of NAb responses in this system. These data demonstrate the immunogenicity of stable, homogeneous clade A and clade C gp140 trimers and exemplify the utility of standardized tier 1 and tier 2 virus panels for assessing the NAb responses of candidate HIV-1 Env immunogens.

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Covalent Linkage of HIV-1 Trimers to Synthetic Liposomes Elicits Improved B Cell and Antibody Responses

Journal of Virology ◽

10.1128/jvi.00443-17 ◽

2017 ◽

Vol 91 (16) ◽

Cited By ~ 31

Author(s):

Shridhar Bale ◽

Geraldine Goebrecht ◽

Armando Stano ◽

Richard Wilson ◽

Takayuki Ota ◽

...

Keyword(s):

B Cells ◽

B Cell ◽

Germinal Center ◽

Neutralizing Antibodies ◽

Tier 2 ◽

Covalent Linkage ◽

His Tag ◽

Hiv 1

ABSTRACT We have demonstrated that a liposomal array of well-ordered trimers enhances B cell activation, germinal center formation, and the elicitation of tier-2 autologous neutralizing antibodies. Previously, we coupled well-ordered cleavage-independent NFL trimers via their C-terminal polyhistidine tails to nickel lipids integrated into the lipid bilayer. Despite favorable in vivo effects, concern remained over the potentially longer-term in vivo instability of noncovalent linkage of the trimers to the liposomes. Accordingly, we tested both cobalt coupling and covalent linkage of the trimers to the liposomes by reengineering the polyhistidine tail to include a free cysteine on each protomer of model BG505 NFL trimers to allow covalent linkage. Both cobalt and cysteine coupling resulted in a high-density array of NFL trimers that was stable in both 20% mouse serum and 100 mM EDTA, whereas the nickel-conjugated trimers were not stable under these conditions. Binding analysis and calcium flux with anti-Env-specific B cells confirmed that the trimers maintained conformational integrity following coupling. Following immunization of mice, serologic analysis demonstrated that the covalently coupled trimers elicited Env-directed antibodies in a manner statistically significantly improved compared to soluble trimers and nickel-conjugated trimers. Importantly, the covalent coupling not only enhanced gp120-directed responses compared to soluble trimers, it also completely eliminated antibodies directed to the C-terminal His tag located at the “bottom” of the spike. In contrast, soluble and noncovalent formats efficiently elicited anti-His tag antibodies. These data indicate that covalent linkage of well-ordered trimers to liposomes in high-density array displays multiple advantages in vitro and in vivo. IMPORTANCE Enveloped viruses typically encode a surface-bound glycoprotein that mediates viral entry into host cells and is a primary target for vaccine design. Liposomes with modified lipid head groups have a unique feature of capturing and displaying antigens on their surfaces, mimicking the native pathogens. Our first-generation nickel-based liposomes captured HIV-1 Env glycoprotein trimers via a noncovalent linkage with improved efficacy over soluble glycoprotein in activating germinal center B cells and eliciting tier-2 autologous neutralizing antibodies. In this study, we report the development of second-generation cobalt- and maleimide-based liposomes that have improved in vitro stability over nickel-based liposomes. In particular, the maleimide liposomes captured HIV-1 Env trimers via a more stable covalent bond, resulting in enhanced germinal center B cell responses that generated higher antibody titers than the soluble trimers and liposome-bearing trimers via noncovalent linkages. We further demonstrate that covalent coupling prevents release of the trimers prior to recognition by B cells and masks a nonneutralizing determinant located at the bottom of the trimer.

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Detection of Broadly Neutralizing Activity within the First Months of HIV-1 Infection

Journal of Virology ◽

10.1128/jvi.00049-16 ◽

2016 ◽

Vol 90 (11) ◽

pp. 5231-5245 ◽

Cited By ~ 12

Author(s):

V. Sanchez-Merino ◽

A. Fabra-Garcia ◽

N. Gonzalez ◽

D. Nicolas ◽

A. Merino-Mansilla ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Geometric Mean ◽

First Year ◽

Tier 2 ◽

Chronic Infections ◽

Neutralizing Activity ◽

Recombinant Viruses ◽

Tier 1 ◽

Tier 3 ◽

Hiv 1

ABSTRACTA fraction of HIV-1 patients are able to generate broadly neutralizing antibodies (bNAbs) after 2 to 4 years of infection. In rare occasions such antibodies are observed close to the first year of HIV-1 infection but never within the first 6 months. In this study, we analyzed the neutralization breadth of sera from 157 antiretroviral-naive individuals who were infected for less than 1 year. A range of neutralizing activities was observed with a previously described panel of six recombinant viruses from five different subtypes (M. Medina-Ramirez et al., J Virol85:5804–5813, 2011,http://dx.doi.org/10.1128/JVI.02482-10). Some sera were broadly reactive, predominantly targeting envelope epitopes within the V2 glycan-dependent region. The neutralization breadth was positively associated with time postinfection (P= 0.0001), but contrary to what has been reported for chronic infections, no association with the viral load was observed. Notably, five individuals within the first 6 months of infection (two as early as 77 and 96 days postinfection) showed substantial cross-neutralization. This was confirmed with an extended panel of 20 Env pseudoviruses from four different subtypes (two in tier 3, 14 in tier 2, and four in tier 1). Sera from these individuals were capable of neutralizing viruses from four different subtypes with a geometric mean 50% infective dose (ID50) between 100 and 800. These results indicate that induction of cross-neutralizing responses, albeit rare, is achievable even within 6 months of HIV-1 infection. These observations encourage the search for immunogens able to elicit this kind of response in preventive HIV-1 vaccine approaches.IMPORTANCEThere are very few individuals able to mount broadly neutralizing activity (bNA) close to the first year postinfection. It is not known how early in the infection cross-neutralizing responses can be induced. In the present study, we show that bNAbs, despite being rare, can be induced much earlier than previously thought. The identification of HIV-1-infected patients with these activities within the first months of infection and characterization of these responses will help in defining new immunogen designs and neutralization targets for vaccine-mediated induction of bNAbs.

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Non-neutralizing antibodies targeting the immunogenic regions of HIV-1 envelope reduce mucosal infection and virus burden in humanized mice

10.1101/2021.05.24.445493 ◽

2021 ◽

Author(s):

Catarina E. Hioe ◽

Guangming Li ◽

Xiaomei Liu ◽

Ourania Tsahouridis ◽

Xiuting He ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Vaccine Trial ◽

Microbial Pathogens ◽

Humanized Mice ◽

Tier 2 ◽

Human Mabs ◽

Hematopoietic Stem ◽

Neutralizing Activity ◽

Hiv 1 ◽

V1v2 Region

Antibodies are principal immune components elicited by vaccines to induce protection from microbial pathogens. In the Thai RV144 HIV-1 vaccine trial, vaccine efficacy was 31% and the sole primary correlate of reduced risk was shown to be vigorous antibody response targeting the V1V2 region of HIV-1 envelope. Antibodies against V3 also were inversely correlated with infection risk in subsets of vaccinees. Antibodies recognizing these regions, however, do not exhibit potent neutralizing activity. Therefore, we examined the antiviral potential of poorly neutralizing monoclonal antibodies (mAbs) against immunodominant V1V2 and V3 sites by passive administration of human mAbs to humanized mice engrafted with CD34+ hematopoietic stem cells, followed by mucosal challenge with an HIV-1 infectious molecular clone (IMC) expressing the envelope of a tier 2 resistant HIV-1 strain. Treatment with anti-V1V2 mAb 2158 or anti-V3 mAb 2219 did not prevent infection, but both reduced the virus burden, and V3 mAb 2219 displayed a superior potency compared to V1V2 mAb 2158. While these mAbs had no or weak neutralizing activity and elicited undetectable levels of antibody-dependent cellular cytotoxicity (ADCC), V3 mAb 2219 displayed a greater capacity to bind virus- and cell-associated HIV-1 envelope and to mediate antibody-dependent cellular phagocytosis (ADCP) and C1q complement binding as compared to V1V2 mAb 2158. Mutations in the Fc region of 2219 abolished these effector activities and abrogated virus control in humanized mice. These results demonstrate the importance of Fc functions other than ADCC for antibodies without potent neutralizing activity.

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Antibody responses induced by SHIV infection are more focused than those induced by soluble native HIV-1 envelope trimers in non-human primates

PLoS Pathogens ◽

10.1371/journal.ppat.1009736 ◽

2021 ◽

Vol 17 (8) ◽

pp. e1009736

Author(s):

Jelle van Schooten ◽

Marlies M. van Haaren ◽

Hui Li ◽

Laura E. McCoy ◽

Colin Havenar-Daughton ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Natural Infection ◽

Neutralizing Antibody ◽

Antibody Responses ◽

Broadly Neutralizing Antibodies ◽

Antibody Diversity ◽

Infected Infant ◽

Immunodeficiency Virus ◽

Shiv Infection ◽

Hiv 1

The development of an effective human immunodeficiency virus (HIV-1) vaccine is a high global health priority. Soluble native-like HIV-1 envelope glycoprotein trimers (Env), including those based on the SOSIP design, have shown promise as vaccine candidates by inducing neutralizing antibody responses against the autologous virus in animal models. However, to overcome HIV-1’s extreme diversity a vaccine needs to induce broadly neutralizing antibodies (bNAbs). Such bNAbs can protect non-human primates (NHPs) and humans from infection. The prototypic BG505 SOSIP.664 immunogen is based on the BG505 env sequence isolated from an HIV-1-infected infant from Kenya who developed a bNAb response. Studying bNAb development during natural HIV-1 infection can inform vaccine design, however, it is unclear to what extent vaccine-induced antibody responses to Env are comparable to those induced by natural infection. Here, we compared Env antibody responses in BG505 SOSIP-immunized NHPs with those in BG505 SHIV-infected NHPs, by analyzing monoclonal antibodies (mAbs). We observed three major differences between BG505 SOSIP immunization and BG505 SHIV infection. First, SHIV infection resulted in more clonal expansion and less antibody diversity compared to SOSIP immunization, likely because of higher and/or prolonged antigenic stimulation and increased antigen diversity during infection. Second, while we retrieved comparatively fewer neutralizing mAbs (NAbs) from SOSIP-immunized animals, these NAbs targeted more diverse epitopes compared to NAbs from SHIV-infected animals. However, none of the NAbs, either elicited by vaccination or infection, showed any breadth. Finally, SOSIP immunization elicited antibodies against the base of the trimer, while infection did not, consistent with the base being placed onto the virus membrane in the latter setting. Together these data provide new insights into the antibody response against BG505 Env during infection and immunization and limitations that need to be overcome to induce better responses after vaccination.

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