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1.
Arch Virol ; 166(5): 1283-1296, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33606110

RESUMO

The lack of progress in finding an efficient vaccine for a human immunodeficiency virus (HIV) is daunting. In fact, this search has spanned nearly four decades without much success. There are several objective reasons for such a failure, which include the highly glycosylated nature of HIV-1, the presence of neotopes, and high mutation rates. This article argues that the presence of highly flexible and intrinsically disordered regions in both human anti-HIV-1 antibodies and the major HIV-1immunogen, its surface glycoprotein gp120, represent one of the major causes for the lack of success in utilization of structure-based reverse vaccinology.


Assuntos
Vacinas contra a AIDS/química , HIV-1/imunologia , Proteínas Intrinsicamente Desordenadas/química , Vacinas contra a AIDS/imunologia , Anticorpos Neutralizantes/química , Anticorpos Neutralizantes/imunologia , Complexo Antígeno-Anticorpo/química , Complexo Antígeno-Anticorpo/imunologia , Anticorpos Anti-HIV/química , Anticorpos Anti-HIV/imunologia , Proteína gp120 do Envelope de HIV/química , Proteína gp120 do Envelope de HIV/imunologia , Infecções por HIV/prevenção & controle , Infecções por HIV/virologia , HIV-1/química , Humanos , Imunoglobulina G/química , Imunoglobulina G/imunologia , Proteínas Intrinsicamente Desordenadas/imunologia
2.
PLoS Pathog ; 16(12): e1009103, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33315937

RESUMO

The antibody molecule comprises a variable domain conferring antigen specificity and affinity distinct from the heavy chain constant (CH) domains dictating effector functions. We here interrogate this paradigm by evaluating the unique influence of the CH1α domain on epitope specificity and functions using two mucosal gp41-specific Fab-IgAs (FabA) derived from HIV-1 highly-exposed but persistently seronegative individuals (HESN). These HESN develop selectively affinity-matured HIV-1-specific mucosal IgA that target the gp41 viral envelope and might provide protection although by unclear mechanisms. Isotype-switching FabAs into Fab-IgGs (FabGs) results in a >10-fold loss in affinity for HIV-1 clade A, B, and C gp41, together with reduced neutralization of HIV-1 cross-clade. The FabA conformational epitopes map selectively on gp41 in 6-Helix bundle and pre-fusion conformations cross-clade, unlike FabGs. Finally, we designed in silico, a 12 amino-acid peptide recapitulating one FabA conformational epitope that inhibits the FabA binding to gp41 cross-clade and its neutralizing activity. Altogether, our results reveal that the CH1α domain shapes the antibody paratope through an allosteric effect, thereby strengthening the antibody specificity and functional activities. Further, they clarify the mechanisms by which these HESN IgAs might confer protection against HIV-1-sexual acquisition. The IgA-specific epitope we characterized by reverse vaccinology could help designing a mucosal HIV-1 vaccine.


Assuntos
Especificidade de Anticorpos/imunologia , Sítios de Ligação de Anticorpos/imunologia , Anticorpos Anti-HIV/imunologia , Infecções por HIV/imunologia , HIV-1/imunologia , Imunoglobulina A/imunologia , Epitopos de Linfócito B/química , Epitopos de Linfócito B/imunologia , Proteína gp41 do Envelope de HIV/imunologia , Soronegatividade para HIV/imunologia , Humanos , Imunoglobulina A/química , Imunoglobulina G/imunologia , Domínios Proteicos/imunologia
3.
PLoS Pathog ; 16(12): e1009185, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33370382

RESUMO

HIV-1 envelope (Env) is a trimer of gp120-gp41 heterodimers, synthesized from a precursor gp160 that contains an ER-targeting signal peptide (SP) at its amino-terminus. Each trimer is swathed by ~90 N-linked glycans, comprising complex-type and oligomannose-type glycans, which play an important role in determining virus sensitivity to neutralizing antibodies. We previously examined the effects of single point SP mutations on Env properties and functions. Here, we aimed to understand the impact of the SP diversity on glycosylation of virus-derived Env and virus neutralization by swapping SPs. Analyses of site-specific glycans revealed that SP swapping altered Env glycan content and occupancy on multiple N-linked glycosites, including conserved N156 and N160 glycans in the V1V2 region at the Env trimer apex and N88 at the trimer base. Virus neutralization was also affected, especially by antibodies against V1V2, V3, and gp41. Likewise, SP swaps affected the recognition of soluble and cell-associated Env by antibodies targeting distinct V1V2 configurations, V3 crown, and gp41 epitopes. These data highlight the contribution of SP sequence diversity in shaping the Env glycan content and its impact on the configuration and accessibility of V1V2 and other Env epitopes.


Assuntos
Epitopos/imunologia , HIV-1/imunologia , Sinais Direcionadores de Proteínas/fisiologia , Produtos do Gene env do Vírus da Imunodeficiência Humana/imunologia , Produtos do Gene env do Vírus da Imunodeficiência Humana/metabolismo , Anticorpos Neutralizantes/imunologia , Glicosilação , Anticorpos Anti-HIV/imunologia , Humanos
4.
Lancet HIV ; 7(10): e688-e698, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-33010242

RESUMO

BACKGROUND: Bioinformatically designed mosaic antigens increase the breadth of HIV vaccine-elicited immunity. This study compared the safety, tolerability, and immunogenicity of a newly developed, tetravalent Ad26 vaccine with the previously tested trivalent formulation. METHODS: This randomised, parallel-group, placebo-controlled, double-blind, phase 1/2a study (TRAVERSE) was done at 11 centres in the USA and one centre in Rwanda. Eligible participants were adults aged 18 to 50 years, who were HIV-uninfected, healthy at screening based on their medical history and a physical examination including laboratory assessment and vital sign measurements, and at low risk of HIV infection in the opinion of study staff, who applied a uniform definition of low-risk guidelines that was aligned across sites. Enrolled participants were randomly assigned at a 2:1 ratio to tetravalent and trivalent groups. Participants in tetravalent and trivalent groups were then further randomly assigned at a 5:1 ratio to adenovirus 26 (Ad26)-vectored vaccine and placebo subgroups. Randomisation was stratified by region (USA and Rwanda) and based on a computer-generated schedule using randomly permuted blocks prepared under the sponsor's supervision. We masked participants and investigators to treatment allocation throughout the study. On day 0, participants received a first injection of tetravalent vaccine (Ad26.Mos4.HIV or placebo) or trivalent vaccine (Ad26.Mos.HIV or placebo), and those injections were repeated 12 weeks later. At week 24, vaccine groups received a third dose of tetravalent or trivalent together with clade C gp140, and this was repeated at week 48, with placebos again administered to the placebo group. All study vaccines and placebo were administered by intramuscular injection in the deltoid muscle. We assessed adverse events in all participants who received at least one study injection (full analysis set) and Env-specific binding antibodies in all participants who received at least the first three vaccinations according to the protocol-specified vaccination schedule, had at least one measured post-dose blood sample collected, and were not diagnosed with HIV during the study (per-protocol set). This study is registered with Clinicaltrials.gov, NCT02788045. FINDINGS: Of 201 participants who were enrolled and randomly assigned, 198 received the first vaccination: 110 were in the tetravalent group, 55 in the trivalent group, and 33 in the placebo group. Overall, 185 (93%) completed two scheduled vaccinations per protocol, 180 (91%) completed three, and 164 (83%) completed four. Solicited, self-limiting local, systemic reactogenicity and unsolicited adverse events were similar in vaccine groups and higher than in placebo groups. All participants in the per-protocol set developed clade C Env binding antibodies after the second vaccination, with higher total IgG titres after the tetravalent vaccine than after the trivalent vaccine (10 413 EU/mL, 95% CI 7284-14 886 in the tetravalent group compared with 5494 EU/mL, 3759-8029 in the trivalent group). Titres further increased after the third and fourth vaccinations, persisting at least through week 72. Other immune responses were also higher with the tetravalent vaccine, including the magnitude and breadth of binding antibodies against a cross-clade panel of Env antigens, and the magnitude of IFNγ ELISPOT responses (median 521 SFU/106 peripheral blood mononuclear cells [PBMCs] in the tetravalent group and median 282 SFU/106 PBMCs in the trivalent group after the fourth vaccination) and Env-specific CD4+ T-cell response rates after the third and fourth vaccinations. No interference by pre-existing Ad26 immunity was identified. INTERPRETATION: The tetravalent vaccine regimen was generally safe, well-tolerated, and found to elicit higher immune responses than the trivalent regimen. Regimens that use this tetravalent vaccine component are being advanced into field trials to assess efficacy against HIV-1 infection. FUNDING: National Institutes of Health, Henry M Jackson Foundation for Advancement of Military Medicine and the US Department of Defense, Ragon Institute of MGH, MIT, & Harvard, Bill & Melinda Gates Foundation, and Janssen Vaccines & Prevention.


Assuntos
Vacinas contra a AIDS/imunologia , Infecções por HIV/imunologia , HIV-1/imunologia , Imunogenicidade da Vacina , Vacinas contra a AIDS/administração & dosagem , Vacinas contra a AIDS/efeitos adversos , Adulto , Feminino , Anticorpos Anti-HIV/imunologia , Infecções por HIV/prevenção & controle , Voluntários Saudáveis , Humanos , Esquemas de Imunização , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento , Vacinação , Adulto Jovem
5.
Nat Commun ; 11(1): 4409, 2020 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-32879304

RESUMO

Broadly neutralizing antibodies (bnAbs) develop in a subset of HIV-1 infected individuals over 2-3 years of infection. Infected infants develop plasma bnAbs frequently and as early as 1-year post-infection suggesting factors governing bnAb induction in infants are distinct from adults. Understanding viral characteristics in infected infants with early bnAb responses will provide key information about antigenic triggers driving B cell maturation pathways towards induction of bnAbs. Herein, we evaluate the presence of plasma bnAbs in a cohort of 51 HIV-1 clade-C infected infants and identify viral factors associated with early bnAb responses. Plasma bnAbs targeting V2-apex on the env are predominant in infant elite and broad neutralizers. Circulating viral variants in infant elite neutralizers are susceptible to V2-apex bnAbs. In infant elite neutralizers, multivariant infection is associated with plasma bnAbs targeting diverse autologous viruses. Our data provides information supportive of polyvalent vaccination approaches capable of inducing V2-apex bnAbs against HIV-1.


Assuntos
Anticorpos Neutralizantes/sangue , Anticorpos Anti-HIV/imunologia , Infecções por HIV/imunologia , Produtos do Gene env do Vírus da Imunodeficiência Humana/imunologia , Estudos de Coortes , Feminino , HIV-1/imunologia , Humanos , Lactente , Transmissão Vertical de Doença Infecciosa , Masculino , Vacinação
6.
PLoS Pathog ; 16(9): e1008764, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32881968

RESUMO

To augment HIV-1 pox-protein vaccine immunogenicity using a next generation adjuvant, a prime-boost strategy of recombinant modified vaccinia virus Ankara and multimeric Env gp145 was evaluated in macaques with either aluminum (alum) or a novel liposomal monophosphoryl lipid A (MPLA) formulation adsorbed to alum, ALFA. Binding antibody responses were robust and comparable between arms, while antibody-dependent neutrophil and monocyte phagocytotic responses were greatly enhanced by ALFA. Per-exposure vaccine efficacy against heterologous tier 2 SHIV mucosal challenge was 90% in ALFA-adjuvanted males (P = 0.002), while alum conferred no protection. Half of the ALFA-adjuvanted males remained uninfected after the full challenge series, which spanned seven months after the last vaccination. Antibody-dependent monocyte and neutrophil phagocytic responses both strongly correlated with protection. Significant sex differences in infection risk were observed, with much lower infection rates in females than males. In humans, MPLA-liposome-alum adjuvanted gp120 also increased HIV-1-specific phagocytic responses relative to alum. Thus, next-generation liposome-based adjuvants can drive vaccine elicited antibody effector activity towards potent phagocytic responses in both macaques and humans and these responses correlate with protection. Future protein vaccination strategies aiming to improve functional humoral responses may benefit from such adjuvants.


Assuntos
Adjuvantes Imunológicos/administração & dosagem , Anticorpos Antivirais/imunologia , Formação de Anticorpos/imunologia , Anticorpos Anti-HIV/imunologia , Infecções por HIV/prevenção & controle , Vacinas contra a SAIDS/uso terapêutico , Síndrome de Imunodeficiência Adquirida dos Símios/prevenção & controle , Adolescente , Adulto , Animais , Anticorpos Neutralizantes/imunologia , Método Duplo-Cego , Feminino , Infecções por HIV/imunologia , Infecções por HIV/virologia , HIV-1/efeitos dos fármacos , HIV-1/imunologia , Humanos , Macaca mulatta , Masculino , Pessoa de Meia-Idade , Vacinas contra a SAIDS/imunologia , Síndrome de Imunodeficiência Adquirida dos Símios/imunologia , Síndrome de Imunodeficiência Adquirida dos Símios/virologia , Vírus da Imunodeficiência Símia/efeitos dos fármacos , Vírus da Imunodeficiência Símia/imunologia , Adulto Jovem
8.
PLoS One ; 15(9): e0238282, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32915788

RESUMO

The number, intensity and order of emergence of HIV-1 specific antibodies in serum or plasma were associated with the stage of HIV-1 infection. In this study, we retrospectively analyzed the HIV-1 confirmatory results tested by western blot (WB) or recombination immunoblot assay (RIBA) in Wuhan, 2012-2018, to access the profiles of HIV-1 specific antibodies. A total of 14432 HIV-suspected serum or plasma samples collected from local hospitals and other HIV screening laboratories were further screened by two 4th generation enzyme-linked immunosorbent assay (ELISA) kits in our laboratory, of which 11068 specimens (76.69%) had at least one positive ELISA result and thereby were finally confirmed with WB or RIBA. RIBA had identified 652 (81.09%) positive and 13 (1.62%) indeterminate cases from July 1, 2014 to January 7, 2015, while WB had identified 8358 (81.43%) positive and 643 (6.26%) indeterminate cases in the other times during 2012-2018. The indeterminate rate of WB was significant higher than that of RIBA (p<0.001). Although the number of HIV-1 infected subjects increased significantly from 2012 (n = 911) to 2018 (n = 1578), the positive rate of HIV-1 antibodies decreased markedly from 70.08% in 2012 to 58.79% in 2018 (p<0.001). The most commonly observed antibody profile was gp160+gp120+p66+(p55+)p51+gp41+p31+p24+p17+ (4131, 49.43%) for WB-MP and gp160+gp120+gp41+p31+p24+p17+ (382, 58.59%) for RIBA-WANTAI, and the absence of reactivity to three possible serologic markers for recent HIV-1 infection, p31, p66, and p51, increased significantly from 2012 to 2018, with the overall rate of 17.03%, 9.40%, and 15.15%, respectively. The suspected acute HIV-1 infection was also observed to be increased in recent years, with an overall rate of 1.00%. Our results indicated the detection rate had decreased for HIV-1 infection, but increased for suspected recent and acute HIV-1 infection during 2012-2018, reflecting the efforts of intervention among high risk population.


Assuntos
Anticorpos Anti-HIV/sangue , Proteína gp120 do Envelope de HIV/imunologia , Proteína gp160 do Envelope de HIV/imunologia , Infecções por HIV/diagnóstico , Soropositividade para HIV/epidemiologia , HIV-1/imunologia , Adolescente , Adulto , Criança , China/epidemiologia , Ensaio de Imunoadsorção Enzimática , Feminino , Anticorpos Anti-HIV/imunologia , Infecções por HIV/sangue , Infecções por HIV/epidemiologia , HIV-1/isolamento & purificação , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Testes Sorológicos , Fatores de Tempo , Adulto Jovem
9.
Proc Natl Acad Sci U S A ; 117(37): 22920-22931, 2020 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-32873644

RESUMO

Animal models of human antigen-specific B cell receptors (BCRs) generally depend on "inferred germline" sequences, and thus their relationship to authentic naive human B cell BCR sequences and affinities is unclear. Here, BCR sequences from authentic naive human VRC01-class B cells from healthy human donors were selected for the generation of three BCR knockin mice. The BCRs span the physiological range of affinities found in humans, and use three different light chains (VK3-20, VK1-5, and VK1-33) found among subclasses of naive human VRC01-class B cells and HIV broadly neutralizing antibodies (bnAbs). The germline-targeting HIV immunogen eOD-GT8 60mer is currently in clinical trial as a candidate bnAb vaccine priming immunogen. To attempt to model human immune responses to the eOD-GT8 60mer, we tested each authentic naive human VRC01-class BCR mouse model under rare human physiological B cell precursor frequency conditions. B cells with high (HuGL18HL) or medium (HuGL17HL) affinity BCRs were primed, recruited to germinal centers, and they affinity matured, and formed memory B cells. Precursor frequency and affinity interdependently influenced responses. Taken together, these experiments utilizing authentic naive human VRC01-class BCRs validate a central tenet of germline-targeting vaccine design and extend the overall concept of the reverse vaccinology approach to vaccine development.


Assuntos
Anticorpos Monoclonais/imunologia , Anticorpos Amplamente Neutralizantes/imunologia , Anticorpos Anti-HIV/imunologia , Receptores de Antígenos de Linfócitos B/imunologia , Vacinas contra a AIDS/imunologia , Sequência de Aminoácidos/genética , Animais , Anticorpos Neutralizantes/imunologia , Linfócitos B/imunologia , Anticorpos Amplamente Neutralizantes/farmacologia , Antígenos CD4/imunologia , Técnicas de Introdução de Genes/métodos , Centro Germinativo/imunologia , Antígenos HIV , Infecções por HIV/imunologia , HIV-1/imunologia , Humanos , Camundongos , Camundongos Endogâmicos , Camundongos Transgênicos , Células Precursoras de Linfócitos B/imunologia , Vacinação/métodos
10.
PLoS Pathog ; 16(8): e1008753, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32866207

RESUMO

The induction of broad and potent immunity by vaccines is the key focus of research efforts aimed at protecting against HIV-1 infection. Soluble native-like HIV-1 envelope glycoproteins have shown promise as vaccine candidates as they can induce potent autologous neutralizing responses in rabbits and non-human primates. In this study, monoclonal antibodies were isolated and characterized from rhesus macaques immunized with the BG505 SOSIP.664 trimer to better understand vaccine-induced antibody responses. Our studies reveal a diverse landscape of antibodies recognizing immunodominant strain-specific epitopes and non-neutralizing neo-epitopes. Additionally, we isolated a subset of mAbs against an epitope cluster at the gp120-gp41 interface that recognize the highly conserved fusion peptide and the glycan at position 88 and have characteristics akin to several human-derived broadly neutralizing antibodies.


Assuntos
Vacinas contra a AIDS/imunologia , Mapeamento de Epitopos , Epitopos/imunologia , Anticorpos Anti-HIV/imunologia , Proteína gp120 do Envelope de HIV/imunologia , Proteína gp41 do Envelope de HIV/imunologia , HIV-1/imunologia , Vacinas contra a AIDS/genética , Animais , Anticorpos Monoclonais Murinos/imunologia , Epitopos/genética , Anticorpos Anti-HIV/genética , Proteína gp41 do Envelope de HIV/genética , HIV-1/genética , Macaca mulatta , Multimerização Proteica/genética , Multimerização Proteica/imunologia
11.
PLoS Pathog ; 16(8): e1008665, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32780770

RESUMO

Two-component, self-assembling nanoparticles represent a versatile platform for multivalent presentation of viral antigens. Computational design of protein nanoparticles with differing sizes and geometries enables combination with antigens of choice to test novel multimerization concepts in immunization strategies where the goal is to improve the induction and maturation of neutralizing antibody lineages. Here, we describe detailed antigenic, structural, and functional characterization of computationally designed tetrahedral, octahedral, and icosahedral nanoparticle immunogens displaying trimeric HIV envelope glycoprotein (Env) ectodomains. Env trimers, based on subtype A (BG505) or consensus group M (ConM) sequences and engineered with SOSIP stabilizing mutations, were fused to an underlying trimeric building block of each nanoparticle. Initial screening yielded one icosahedral and two tetrahedral nanoparticle candidates, capable of presenting twenty or four copies of the Env trimer. A number of analyses, including detailed structural characterization by cryo-EM, demonstrated that the nanoparticle immunogens possessed the intended structural and antigenic properties. When the immunogenicity of ConM-SOSIP trimers presented on a two-component tetrahedral nanoparticle or as soluble proteins were compared in rabbits, the two immunogens elicited similar serum antibody binding titers against the trimer component. Neutralizing antibody titers were slightly elevated in the animals given the nanoparticle immunogen and were initially more focused to the trimer apex. Altogether, our findings indicate that tetrahedral nanoparticles can be successfully applied for presentation of HIV Env trimer immunogens; however, the optimal implementation to different immunization strategies remains to be determined.


Assuntos
Anticorpos Anti-HIV/imunologia , Antígenos HIV/imunologia , Infecções por HIV/imunologia , HIV-1/imunologia , Nanopartículas/química , Produtos do Gene env do Vírus da Imunodeficiência Humana/química , Produtos do Gene env do Vírus da Imunodeficiência Humana/imunologia , Animais , Epitopos/imunologia , Feminino , Infecções por HIV/virologia , Humanos , Imunização , Nanopartículas/administração & dosagem , Coelhos , Produtos do Gene env do Vírus da Imunodeficiência Humana/genética
12.
PLoS One ; 15(8): e0237580, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32790740

RESUMO

BACKGROUND: HIV screening (i.e. antigen/antibody) tests are followed by a supplemental (i.e. antibody-only) if the screen is positive. Discrepant results can result from two scenarios: a false-positive screening test or acute HIV infection. These scenarios can be distinguished by a molecular HIV test, but due to contamination concerns, our laboratory recently implemented a policy requiring a second specimen dedicated for molecular HIV testing. Our objective was to (1) characterize the effect of this policy on the time-to-diagnosis for patients with discrepant screening and supplemental test results, and (2) explore "strength of positivity" as an interim predictor of screening test accuracy while awaiting confirmatory test results. METHODS: Data from our laboratory information system, electronic health record, and instrument logs were used to collate data for all HIV testing performed at Barnes-Jewish Hospital (BJH) between January 1, 2014 and October 18, 2017. RESULTS: Requiring a dedicated specimen for molecular testing significantly increased the time-to-diagnosis for patients with discrepant screening and supplemental HIV tests (p = 0.0084). This policy also contributed to loss-to-followup, with 0/35 discrepant cases lost-to-followup prior to policy implementation compared to 2/10 after implementation. However, by optimizing the signal-to-cutoff (S/CO) ratio of the screening test, we were able to more accurately distinguish false-positives from acute-HIV prior to molecular testing (sensitivity of 100%, specificity of 89%). CONCLUSIONS: We propose utilizing quantitative fourth-generation assay results (S/CO) ratios as a predictor of infection true positivity in situations where the screening assay is reactive but the supplemental test is negative and confirmatory molecular results are not immediately available.


Assuntos
Sorodiagnóstico da AIDS/normas , Anticorpos Anti-HIV/sangue , Antígenos HIV/imunologia , Infecções por HIV/diagnóstico , Infecções por HIV/prevenção & controle , HIV-1/imunologia , Programas de Rastreamento/métodos , Algoritmos , Reações Falso-Positivas , Anticorpos Anti-HIV/imunologia , Infecções por HIV/sangue , Infecções por HIV/virologia , Humanos
13.
Virology ; 548: 152-159, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32838936

RESUMO

Despite anti-retroviral therapy (ART) interventions for HIV+ pregnant mothers, over 43,000 perinatal infections occur yearly. Understanding risk factors that lead to mother-to-child transmission (MTCT) of HIV are critical. We evaluated maternal and infant plasma binding and neutralizing antibody responses in a drug-naïve, CRF01_AE infected MTCT cohort from Thailand to determine associations with transmission risk. Env V3-specific IgG and neutralizing antibody responses were significantly higher in HIV- infants, as compared to HIV+ infants. In fact, infant plasma neutralizing antibodies significantly associated with non-transmission. Conversely, increased maternal Env V3-specific IgG and neutralizing antibody responses were significantly associated with increased transmission risk, after controlling for maternal viral load. Our results highlight the importance of evaluating both maternal and infant humoral immune responses to better understand mechanisms of protection, as selective placental antibody transport may have a role in MTCT. This study further emphasizes the complex role of Env-specific antibodies in MTCT of CRF01_AE HIV.


Assuntos
Anticorpos Neutralizantes/imunologia , Anticorpos Anti-HIV/imunologia , Infecções por HIV/imunologia , Infecções por HIV/transmissão , HIV-1/imunologia , Adulto , Estudos de Coortes , Feminino , Infecções por HIV/virologia , HIV-1/genética , Humanos , Lactente , Recém-Nascido , Transmissão Vertical de Doença Infecciosa/estatística & dados numéricos , Masculino , Gravidez , Complicações Infecciosas na Gravidez , Tailândia/epidemiologia , Adulto Jovem
14.
Virology ; 548: 73-81, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32838948

RESUMO

The host protein SERINC5 inhibits the infectivity of HIV-1 virions in an Env-dependent manner and is counteracted by Nef. The conformation of the Env trimer reportedly correlates with sensitivity to SERINC5. Here, we tested the hypothesis that the "open" conformation of the Env trimer revealed by sensitivity to the V3-loop specific antibody 447-52D directly correlates with sensitivity to SERINC5. Of five Envs tested, SF162 was the most sensitive to neutralization by 447-52D, but it was not the most sensitive to SERINC5; instead the Env of LAI was substantially more sensitive to SERINC5 than all the other Envs. Mutational opening of the trimer by substitution of two tyrosines that mediate interaction between the V2 and V3 loops sensitized the Envs of JRFL and LAI to 447-52D as previously reported, but only BaL was sensitized to SERINC5. These data suggest that trimer "openness" is not sufficient for sensitivity to SERINC5.


Assuntos
Anticorpos Monoclonais/imunologia , Anticorpos Anti-HIV/imunologia , Infecções por HIV/imunologia , HIV-1/imunologia , Proteínas de Membrana/imunologia , Produtos do Gene env do Vírus da Imunodeficiência Humana/química , Produtos do Gene env do Vírus da Imunodeficiência Humana/imunologia , Anticorpos Neutralizantes/imunologia , Infecções por HIV/genética , Infecções por HIV/virologia , HIV-1/química , HIV-1/genética , HIV-1/fisiologia , Humanos , Proteínas de Membrana/química , Proteínas de Membrana/genética , Mutação , Produtos do Gene env do Vírus da Imunodeficiência Humana/genética
15.
Proc Natl Acad Sci U S A ; 117(30): 18002-18009, 2020 07 28.
Artigo em Inglês | MEDLINE | ID: mdl-32665438

RESUMO

In combating viral infections, the Fab portion of an antibody could mediate virus neutralization, whereas Fc engagement of Fc-γ receptors (FcγRs) could mediate an array of effector functions. Evidence abounds that effector functions are important in controlling infections by influenza, Ebola, or HIV-1 in animal models. However, the relative contribution of virus neutralization versus effector functions to the overall antiviral activity of an antibody remains unknown. To address this fundamental question in immunology, we utilized our knowledge of HIV-1 dynamics to compare the kinetics of the viral load decline (ΔVL) in infected animals given a wild-type (WT) anti-HIV-1 immunoglobulin G1 (IgG1) versus those given a Fc-Null variant of the same antibody. In three independent experiments in HIV-1-infected humanized mice and one pivotal experiment in simian-human immunodeficiency virus (SHIV)-infected rhesus macaques, an earlier and sharper decline in viral load was consistently detected for the WT antibody. Quantifications of the observed differences indicate that Fc-mediated effector functions accounted for 25-45% of the total antiviral activity in these separate experiments. In this study, Fc-mediated effector functions have been quantified in vivo relative to the contribution of virus neutralization mediated by the Fab.


Assuntos
Anticorpos Anti-HIV/imunologia , Infecções por HIV/imunologia , Infecções por HIV/metabolismo , HIV-1/imunologia , Imunoglobulina G/imunologia , Receptores de IgG/metabolismo , Animais , Anticorpos Neutralizantes/imunologia , Modelos Animais de Doenças , Infecções por HIV/virologia , Interações Hospedeiro-Patógeno/imunologia , Humanos , Camundongos , Camundongos Transgênicos , Testes de Neutralização
16.
Proc Natl Acad Sci U S A ; 117(31): 18754-18763, 2020 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-32690707

RESUMO

Treatment of HIV infection with either antiretroviral (ARV) therapy or neutralizing monoclonal antibodies (NAbs) leads to a reduction in HIV plasma virus. Both ARVs and NAbs prevent new rounds of viral infection, but NAbs may have the additional capacity to accelerate the loss of virus-infected cells through Fc gamma receptor (FcγR)-mediated effector functions, which should affect the kinetics of plasma-virus decline. Here, we formally test the role of effector function in vivo by comparing the rate and timing of plasma-virus clearance in response to a single-dose treatment with either unmodified NAb or those with either reduced or augmented Fc function. When infused into viremic simian HIV (SHIV)-infected rhesus macaques, there was a 21% difference in slope of plasma-virus decline between NAb and NAb with reduced Fc function. NAb engineered to increase FcγRIII binding and improve antibody-dependent cellular cytotoxicity (ADCC) in vitro resulted in arming of effector cells in vivo, yet led to viral-decay kinetics similar to NAbs with reduced Fc function. These studies show that the predominant mechanism of antiviral activity of HIV NAbs is through inhibition of viral entry, but that Fc function can contribute to the overall antiviral activity, making them distinct from standard ARVs.


Assuntos
Anticorpos Neutralizantes/imunologia , Anticorpos Anti-HIV/imunologia , Infecções por HIV , HIV-1/imunologia , Receptores de IgG/imunologia , Animais , Citotoxicidade Celular Dependente de Anticorpos/imunologia , Células Cultivadas , Modelos Animais de Doenças , Infecções por HIV/imunologia , Infecções por HIV/virologia , Humanos , Leucócitos Mononucleares/imunologia , Leucócitos Mononucleares/virologia , Macaca mulatta , Síndrome de Imunodeficiência Adquirida dos Símios , Vírus da Imunodeficiência Símia
17.
J Virol ; 94(17)2020 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-32522853

RESUMO

The human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein (Env) trimer of gp120-gp41 heterodimers mediates virus entry into CD4-positive (CD4+) cells. Single-molecule fluorescence resonance energy transfer (smFRET) has revealed that native Env on the surface of viruses predominantly exists in a pretriggered conformation (state 1) that is preferentially recognized by many broadly neutralizing antibodies (bNAbs). Env is activated by binding receptor CD4, which drives transitions through a default intermediate conformation (state 2) into the three-CD4-bound open conformation (state 3). The application of smFRET to assess the conformational state of existing Env constructs and ligand complexes recently revealed that all current high-resolution structures correspond to downstream states 2 and 3. The structure of state 1, therefore, remains unknown. We sought to identify conditions whereby HIV-1 Env could be stabilized in the pretriggered state 1 for possible structural characterization. Shedding of gp120, known to severely complicate structural studies, can be prevented by using the uncleaved gp160JR-FL precursor with alterations in the protease cleavage site (R508S/R511S) or by introducing a disulfide bridge between gp120 and gp41 designated "SOS" (A501C/T605C). smFRET demonstrated that both shedding-preventing modifications shifted the conformational landscape of Env downstream toward states 2 and 3. However, both membrane-bound Env proteins on the surface of intact viruses remained conformationally dynamic, responsive to state-stabilizing ligands, and able to be stabilized in state 1 by specific ligands such as the Bristol-Myers Squibb (BMS) entry inhibitors. The here-described identification of state 1-stabilizing conditions may enable structural characterization of the state 1 conformation of HIV-1 Env.IMPORTANCE The HIV-1 envelope glycoprotein (Env) opens in response to receptor CD4 binding from a pretriggered (state 1) conformation through a necessary intermediate to the three-CD4-bound conformation. The application of smFRET to test the conformational state of existing Env constructs and ligand complexes used for high-resolution structures recently revealed that they correspond to the downstream conformations. The structure of the pretriggered Env conformation, preferentially recognized by broadly neutralizing antibodies, remains unknown. Here, we identify experimental conditions that stabilize membrane-bound and shedding-resistant virus Env trimers in state 1, potentially facilitating structural characterization of this unknown conformational state.


Assuntos
Glicoproteínas/química , Glicoproteínas/imunologia , HIV-1/imunologia , Eliminação de Partículas Virais/imunologia , Eliminação de Partículas Virais/fisiologia , Anticorpos Neutralizantes/imunologia , Antígenos CD4 , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/virologia , Dissulfetos , Células HEK293 , Anticorpos Anti-HIV/imunologia , Proteína gp120 do Envelope de HIV/química , Proteína gp120 do Envelope de HIV/imunologia , Proteína gp41 do Envelope de HIV/química , Proteína gp41 do Envelope de HIV/imunologia , Humanos , Ligantes , Modelos Moleculares , Ligação Proteica , Conformação Proteica , Internalização do Vírus , Produtos do Gene env do Vírus da Imunodeficiência Humana/imunologia
18.
PLoS One ; 15(6): e0231679, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32559193

RESUMO

The envelope glycoprotein (Env) of the human immunodeficiency virus (HIV), has been the primary target for the development of a protective vaccine against infection. The extensive N-linked glycosylation on Env is an important consideration as it may affect efficacy, stability, and expression yields. The expression host has been shown to influence the extent and type of glycosylation that decorates the protein target. Here, we report the glycosylation profile of the candidate subtype C immunogen CO6980v0c22 gp145, which is currently in Phase I clinical trials, produced in two different host cells: CHO-K1 and Expi293F. The amino acid sequence for both glycoproteins was confirmed to be identical by peptide mass fingerprinting. However, the isoelectric point of the proteins differed; 4.5-5.5 and 6.0-7.0 for gp145 produced in CHO-K1 and Expi293F, respectively. These differences in pI were eliminated by enzymatic treatment with sialidase, indicating a large difference in the incorporation of sialic acid between hosts. This dramatic difference in the number of sialylated glycans between hosts was confirmed by analysis of PNGase F-released glycans using MALDI-ToF MS. These differences in glycosylation, however, did not greatly translate into differences in antibody recognition. Biosensor assays showed that gp145 produced in CHO-K1 had similar affinity toward the broadly neutralizing antibodies, 2G12 and PG16, as the gp145 produced in Expi293F. Additionally, both immunogens showed the same reactivity against plasma of HIV-infected patients. Taken together, these results support the notion that there are sizeable differences in the glycosylation of Env depending on the expression host. How these differences translate to vaccine efficacy remains unknown.


Assuntos
Glicopeptídeos/análise , Anticorpos Anti-HIV/imunologia , HIV-1/metabolismo , Produtos do Gene env do Vírus da Imunodeficiência Humana/imunologia , Adulto , Animais , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , Reações Antígeno-Anticorpo , Células CHO , Cricetinae , Cricetulus , Feminino , Glicosilação , Células HEK293 , Humanos , Pessoa de Meia-Idade , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/imunologia , Proteínas Recombinantes/isolamento & purificação , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Adulto Jovem , Produtos do Gene env do Vírus da Imunodeficiência Humana/genética , Produtos do Gene env do Vírus da Imunodeficiência Humana/metabolismo
19.
J Virol ; 94(17)2020 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-32554699

RESUMO

The HIV vaccine field now recognizes the potential importance of generating polyfunctional antibodies (Abs). The only clinical HIV vaccine trial to date to show significant efficacy (RV144) found that reduced infection rates correlated with the level of nonneutralizing Abs specific for the V2 region of the envelope glycoprotein. We have conducted a comprehensive preclinical reverse vaccinology-based vaccine program that has included the design and production and testing of numerous scaffolded V2 region immunogens. The most immunogenic vaccine regimen in nonhuman primates among those studied as part of this program consisted of a cocktail of three immunogens presenting V2 from different viruses and clades in the context of different scaffolds. Presently we demonstrate that the V2-specific Ab response from this regimen was highly durable and functionally diverse for the duration of the study (25 weeks after the final immunization). The total IgG binding response at this late time point exhibited only an ∼5× reduction in potency. Three immunizations appeared essential for the elicitation of a strong Ab-dependent cellular cytotoxicity (ADCC) response for all animals, as opposed to the Ab-dependent cellular phagocytosis (ADCP) and virus capture responses, which were comparably potent after only 2 immunizations. All functionalities measured were highly durable through the study period. Therefore, testing this vaccine candidate for its protective capacity is warranted.IMPORTANCE The only HIV vaccine trial for which protective efficacy was detected correlated this efficacy with V2-specific Abs that were effectively nonneutralizing. This result has fueled a decade of HIV vaccine research focused on designing an HIV vaccine capable of eliciting V2-focused, polyfunctional Abs that effectively bind HIV and trigger various leukocytes to kill the virus and restrict viral spread. From the numerous vaccine candidates designed and tested as part of our V2-focused preclinical vaccine program, we have identified immunogens and a vaccine regimen that induces a highly durable and polyfunctional V2-focused Ab response in rhesus macaques, described herein.


Assuntos
Vacinas contra a AIDS/imunologia , Anticorpos Anti-HIV/imunologia , Antígenos HIV/imunologia , HIV-1/imunologia , Fragmentos Fc das Imunoglobulinas/imunologia , Macaca mulatta/imunologia , Proteínas do Envelope Viral/imunologia , Animais , Formação de Anticorpos , Modelos Animais de Doenças , Antígenos HIV/genética , Proteína gp120 do Envelope de HIV/genética , Proteína gp120 do Envelope de HIV/imunologia , Infecções por HIV/imunologia , Infecções por HIV/prevenção & controle , Imunização , Imunogenicidade da Vacina/imunologia , Proteínas do Envelope Viral/genética
20.
PLoS Med ; 17(5): e1003117, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32442195

RESUMO

BACKGROUND: DNA plasmids promise a pragmatic alternative to viral vectors for prime-boost HIV-1 vaccines. We evaluated DNA plasmid versus canarypox virus (ALVAC) primes in 2 randomized, double-blind, placebo-controlled trials in southern Africa with harmonized trial designs. HIV Vaccine Trials Network (HVTN) 111 tested DNA plasmid prime by needle or needleless injection device (Biojector) and DNA plasmid plus gp120 protein plus MF59 adjuvant boost. HVTN 100 tested ALVAC prime and ALVAC plus gp120 protein plus MF59 adjuvant boost (same protein/adjuvant as HVTN 111) by needle. METHODS AND FINDINGS: The primary endpoints for this analysis were binding antibody (bAb) responses to HIV antigens (gp120 from strains ZM96, 1086, and TV1; variable 1 and 2 [V1V2] regions of gp120 from strains TV1, 1086, and B.CaseA, as 1086 V1V2 and B.CaseA were correlates of risk in the RV144 efficacy trial), neutralizing antibody (nAb) responses to pseudoviruses TV1c8.2 and MW925.26, and cellular responses to vaccine-matched antigens (envelope [Env] from strains ZM96, 1086, and TV1; and Gag from strains LAI and ZM96) at month 6.5, two weeks after the fourth vaccination. Per-protocol cohorts included vaccine recipients from HVTN 100 (n = 186, 60% male, median age 23 years) enrolled between February 9, 2015, and May 26, 2015 and from HVTN 111 (n = 56, 48% male, median age 24 years) enrolled between June 21, 2016, and July 13, 2017. IgG bAb response rates were 100% to 3 Env gp120 antigens in both trials. Response rates to V1V2 were lower and similar in both trials except to vaccine-matched 1086 V1V2, with rates significantly higher for the DNA-primed regimen than the ALVAC-primed regimen: 96.6% versus 72.7% (difference = 23.9%, 95% CI 15.6%-32.2%, p < 0.001). Among positive responders, bAb net mean fluorescence intensity (MFI) was significantly higher with the DNA-primed regimen than ALVAC-primed for 1086 V1V2 (geometric mean [GM] 2,833.3 versus 1,200.9; ratio = 2.36, 95% CI 1.42-3.92, p < 0.001) and B.CaseA V1V2 (GM 2314.0 versus 744.6, ratio = 3.11, 95% CI 1.51-6.38, p = 0.002). nAb response rates were >98% in both trials, with significantly higher 50% inhibitory dilution (ID50) among DNA-primed positive responders (n = 53) versus ALVAC-primed (n = 182) to tier 1A MW965.26 (GM 577.7 versus 265.7, ratio = 2.17, 95% CI 1.67-2.83, p < 0.001) and to TV1c8.2 (GM 187.3 versus 100.4, ratio = 1.87, 95% CI 1.48-2.35, p < 0.001). CD4+ T-cell response rates were significantly higher with DNA plasmid prime via Biojector than ALVAC prime (91.4% versus 52.8%, difference = 38.6%, 95% CI 20.5%-56.6%, p < 0.001 for ZM96.C; 88.0% versus 43.1%, difference = 44.9%, 95% CI 26.7%-63.1%, p < 0.001 for 1086.C; 55.5% versus 2.2%, difference = 53.3%, 95% CI 23.9%-82.7%, p < 0.001 for Gag LAI/ZM96). The study's main limitations include the nonrandomized comparison of vaccines from 2 different trials, the lack of data on immune responses to other non-vaccine-matched antigens, and the uncertain clinical significance of the observed immunological effects. CONCLUSIONS: In this study, we found that further investigation of DNA/protein regimens is warranted given enhanced immunogenicity to the V1V2 correlates of decreased HIV-1 acquisition risk identified in RV144, the only HIV vaccine trial to date to show any efficacy.


Assuntos
Vacinas contra a AIDS/imunologia , Anticorpos Neutralizantes/imunologia , Anticorpos Anti-HIV/imunologia , Adulto , Formação de Anticorpos/imunologia , DNA/genética , Método Duplo-Cego , Feminino , Vetores Genéticos , Antígenos HIV/imunologia , Infecções por HIV/prevenção & controle , HIV-1/genética , HIV-1/imunologia , Humanos , Masculino , Plasmídeos/genética , Vacinação/métodos , Adulto Jovem
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